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Initial commit: AOSP 12 vendor with modifications for Unplugged OS
2025-10-06 13:59:42 +00:00
This is
/home/xpgcust/tree/RI-2019.1/ib/p4root/Xtensa/SWConfig/../Target-libs/newlib/newlib/libc/libc.info,
produced by makeinfo version 4.8 from
/home/xpgcust/tree/RI-2019.1/ib/p4root/Xtensa/SWConfig/../Target-libs/newlib/newlib/libc/libc.texinfo.
10/2018
This file documents the ANSI C library, version 2.20.0 for Xtensa(R)
Tools Version 14.2.
Copyright (C) 1992, 1993, 1994-2012 Red Hat, Inc. Copyright (C)
1999-2012 Tensilica, Inc.
`libc' includes software developed by the University of California,
Berkeley and its contributors.
libc includes software developed by Martin Jackson, Graham Haley and
Steve Chamberlain of Tadpole Technology and released to Cygnus.
libc uses floating-point conversion software developed at AT&T, which
includes this copyright information:
The author of this software is David M. Gay.
Copyright (c) 1991 by AT&T.
Permission to use, copy, modify, and distribute this software for any
purpose without fee is hereby granted, provided that this entire notice
is included in all copies of any software which is or includes a copy
or modification of this software and in all copies of the supporting
documentation for such software.
THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
IMPLIED WARRANTY. IN PARTICULAR, NEITHER THE AUTHOR NOR AT&T MAKES ANY
REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of
this manual under the conditions for verbatim copying, subject to the
terms of the GNU General Public License, which includes the provision
that the entire resulting derived work is distributed under the terms
of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this
manual into another language, under the above conditions for modified
versions.
This publication is provided "AS IS." Tensilica, Inc. (hereafter
"Tensilica") does not make any warranty of any kind, either expressed
or implied, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Information in
this document is provided solely to enable system and software
developers to use Tensilica(R) processors. Unless specifically set
forth herein, there are no express or implied patent, copyright or any
other intellectual property rights or licenses granted hereunder to
design or fabricate Tensilica integrated circuits or integrated
circuits based on the information in this document. Tensilica does not
warrant that the contents of this publication, whether individually or
as one or more groups, meets your requirements or that the publication
is error-free. This publication could include technical inaccuracies
or typographical errors. Changes may be made to the information
herein, and these changes may be incorporated in new editions of this
publication.
The following terms are trademarks or registered trademarks of
Tensilica, Inc.: FLIX, OSKit, Sea of Processors, Tensilica, Vectra,
Xplorer, XPRES, and Xtensa. All other trademarks and registered
trademarks are the property of their respective companies.

File: libc.info, Node: strrchr, Next: strsignal, Prev: strpbrk, Up: Strings
5.34 `strrchr'--reverse search for character in string
======================================================
*Synopsis*
#include <string.h>
char * strrchr(const char *STRING, int C);
*Description*
This function finds the last occurence of C (converted to a char) in
the string pointed to by STRING (including the terminating null
character).
*Returns*
Returns a pointer to the located character, or a null pointer if C does
not occur in STRING.
*Portability*
`strrchr' is ANSI C.
`strrchr' requires no supporting OS subroutines.

File: libc.info, Node: strsignal, Next: strspn, Prev: strrchr, Up: Strings
5.35 `strsignal'--convert signal number to string
=================================================
*Synopsis*
#include <string.h>
char *strsignal(int SIGNAL);
*Description*
`strsignal' converts the signal number SIGNAL into a string. If SIGNAL
is not a known signal number, the result will be of the form "Unknown
signal NN" where NN is the SIGNAL is a decimal number.
*Returns*
This function returns a pointer to a string. Your application must not
modify that string.
*Portability*
POSIX.1-2008 C requires `strsignal', but does not specify the strings
used for each signal number.
`strsignal' requires no supporting OS subroutines.

File: libc.info, Node: strspn, Next: strstr, Prev: strsignal, Up: Strings
5.36 `strspn'--find initial match
=================================
*Synopsis*
#include <string.h>
size_t strspn(const char *S1, const char *S2);
*Description*
This function computes the length of the initial segment of the string
pointed to by S1 which consists entirely of characters from the string
pointed to by S2 (excluding the terminating null character).
*Returns*
`strspn' returns the length of the segment found.
*Portability*
`strspn' is ANSI C.
`strspn' requires no supporting OS subroutines.

File: libc.info, Node: strstr, Next: strtok, Prev: strspn, Up: Strings
5.37 `strstr'--find string segment
==================================
*Synopsis*
#include <string.h>
char *strstr(const char *S1, const char *S2);
*Description*
Locates the first occurrence in the string pointed to by S1 of the
sequence of characters in the string pointed to by S2 (excluding the
terminating null character).
*Returns*
Returns a pointer to the located string segment, or a null pointer if
the string S2 is not found. If S2 points to a string with zero length,
S1 is returned.
*Portability*
`strstr' is ANSI C.
`strstr' requires no supporting OS subroutines.

File: libc.info, Node: strtok, Next: strupr, Prev: strstr, Up: Strings
5.38 `strtok', `strtok_r', `strsep'--get next token from a string
=================================================================
*Synopsis*
#include <string.h>
char *strtok(char *SOURCE, const char *DELIMITERS)
char *strtok_r(char *SOURCE, const char *DELIMITERS,
char **LASTS)
char *strsep(char **SOURCE_PTR, const char *DELIMITERS)
*Description*
The `strtok' function is used to isolate sequential tokens in a
null-terminated string, `*SOURCE'. These tokens are delimited in the
string by at least one of the characters in `*DELIMITERS'. The first
time that `strtok' is called, `*SOURCE' should be specified; subsequent
calls, wishing to obtain further tokens from the same string, should
pass a null pointer instead. The separator string, `*DELIMITERS', must
be supplied each time and may change between calls.
The `strtok' function returns a pointer to the beginning of each
subsequent token in the string, after replacing the separator character
itself with a null character. When no more tokens remain, a null
pointer is returned.
The `strtok_r' function has the same behavior as `strtok', except a
pointer to placeholder `*LASTS' must be supplied by the caller.
The `strsep' function is similar in behavior to `strtok', except a
pointer to the string pointer must be supplied `SOURCE_PTR' and the
function does not skip leading delimiters. When the string starts with
a delimiter, the delimiter is changed to the null character and the
empty string is returned. Like `strtok_r' and `strtok', the
`*SOURCE_PTR' is updated to the next character following the last
delimiter found or NULL if the end of string is reached with no more
delimiters.
*Returns*
`strtok', `strtok_r', and `strsep' all return a pointer to the next
token, or `NULL' if no more tokens can be found. For `strsep', a token
may be the empty string.
*Portability*
`strtok' is ANSI C. `strtok_r' is POSIX. `strsep' is a BSD extension.
`strtok', `strtok_r', and `strsep' require no supporting OS
subroutines.

File: libc.info, Node: strupr, Next: strxfrm, Prev: strtok, Up: Strings
5.39 `strupr'--force string to uppercase
========================================
*Synopsis*
#include <string.h>
char *strupr(char *A);
*Description*
`strupr' converts each character in the string at A to uppercase.
*Returns*
`strupr' returns its argument, A.
*Portability*
`strupr' is not widely portable.
`strupr' requires no supporting OS subroutines.

File: libc.info, Node: strxfrm, Next: swab, Prev: strupr, Up: Strings
5.40 `strxfrm'--transform string
================================
*Synopsis*
#include <string.h>
size_t strxfrm(char *S1, const char *S2, size_t N);
*Description*
This function transforms the string pointed to by S2 and places the
resulting string into the array pointed to by S1. The transformation is
such that if the `strcmp' function is applied to the two transformed
strings, it returns a value greater than, equal to, or less than zero,
correspoinding to the result of a `strcoll' function applied to the
same two original strings.
No more than N characters are placed into the resulting array
pointed to by S1, including the terminating null character. If N is
zero, S1 may be a null pointer. If copying takes place between objects
that overlap, the behavior is undefined.
With a C locale, this function just copies.
*Returns*
The `strxfrm' function returns the length of the transformed string
(not including the terminating null character). If the value returned
is N or more, the contents of the array pointed to by S1 are
indeterminate.
*Portability*
`strxfrm' is ANSI C.
`strxfrm' requires no supporting OS subroutines.

File: libc.info, Node: swab, Next: wcscasecmp, Prev: strxfrm, Up: Strings
5.41 `swab'--swap adjacent bytes
================================
*Synopsis*
#include <unistd.h>
void swab(const void *IN, void *OUT, ssize_t N);
*Description*
This function copies N bytes from the memory region pointed to by IN to
the memory region pointed to by OUT, exchanging adjacent even and odd
bytes.
*Portability*
`swab' requires no supporting OS subroutines.

File: libc.info, Node: wcscasecmp, Next: wcsdup, Prev: swab, Up: Strings
5.42 `wcscasecmp'--case-insensitive wide character string compare
=================================================================
*Synopsis*
#include <wchar.h>
int wcscasecmp(const wchar_t *A, const wchar_t *B);
*Description*
`wcscasecmp' compares the wide character string at A to the wide
character string at B in a case-insensitive manner.
*Returns*
If `*A' sorts lexicographically after `*B' (after both are converted to
uppercase), `wcscasecmp' returns a number greater than zero. If the
two strings match, `wcscasecmp' returns zero. If `*A' sorts
lexicographically before `*B', `wcscasecmp' returns a number less than
zero.
*Portability*
POSIX-1.2008
`wcscasecmp' requires no supporting OS subroutines. It uses
tolower() from elsewhere in this library.

File: libc.info, Node: wcsdup, Next: wcsncasecmp, Prev: wcscasecmp, Up: Strings
5.43 `wcsdup'--wide character string duplicate
==============================================
*Synopsis*
#include <wchar.h>
wchar_t *wcsdup(const wchar_t *STR);
#include <wchar.h>
wchar_t *_wcsdup_r(struct _reent *PTR, const wchar_t *STR);
*Description*
`wcsdup' allocates a new wide character string using `malloc', and
copies the content of the argument STR into the newly allocated string,
thus making a copy of STR.
*Returns*
`wcsdup' returns a pointer to the copy of STR if enough memory for the
copy was available. Otherwise it returns NULL and errno is set to
ENOMEM.
*Portability*
POSIX-1.2008

File: libc.info, Node: wcsncasecmp, Prev: wcsdup, Up: Strings
5.44 `wcsncasecmp'--case-insensitive wide character string compare
==================================================================
*Synopsis*
#include <wchar.h>
int wcsncasecmp(const wchar_t *A, const wchar_t * B, size_t LENGTH);
*Description*
`wcsncasecmp' compares up to LENGTH wide characters from the string at
A to the string at B in a case-insensitive manner.
*Returns*
If `*A' sorts lexicographically after `*B' (after both are converted to
uppercase), `wcsncasecmp' returns a number greater than zero. If the
two strings are equivalent, `wcsncasecmp' returns zero. If `*A' sorts
lexicographically before `*B', `wcsncasecmp' returns a number less than
zero.
*Portability*
POSIX-1.2008
`wcsncasecmp' requires no supporting OS subroutines. It uses
tolower() from elsewhere in this library.

File: libc.info, Node: Wchar strings, Next: Signals, Prev: Strings, Up: Top
6 Wide Character Strings (`wchar.h')
************************************
This chapter describes wide-character string-handling functions and
managing areas of memory containing wide characters. The corresponding
declarations are in `wchar.h'.
* Menu:
* wmemchr:: Find wide character in memory
* wmemcmp:: Compare two wide-character memory areas
* wmemcpy:: Copy wide-character memory regions
* wmemmove:: Move possibly overlapping wide-character memory
* wmemset:: Set an area of memory to a specified wide character
* wcscat:: Concatenate wide-character strings
* wcschr:: Search for wide character in string
* wcscmp:: Wide-character string compare
* wcscoll:: Locale-specific wide-character string compare
* wcscpy:: Copy wide-character string
* wcpcpy:: Copy a wide-character string returning a pointer to its end
* wcscspn:: Count wide characters not in string
* wcsftime:: Convert date and time to a formatted wide-character string
* wcslcat:: Concatenate wide-character strings to specified length
* wcslcpy:: Copy wide-character string to specified length
* wcslen:: Wide-character string length
* wcsncat:: Concatenate wide-character strings
* wcsncmp:: Wide-character string compare
* wcsncpy:: Counted copy wide-character string
* wcpncpy:: Copy part of a wide-character string returning a pointer to its end
* wcsnlen:: Wide-character string length with maximum limit
* wcspbrk:: Find wide characters in string
* wcsrchr:: Reverse search for wide character in string
* wcsspn:: Find initial match in wide-character string
* wcsstr:: Find wide-character string segment
* wcstok:: Tokenize wide-character string
* wcswidth:: Number of column positions of a wide-character string
* wcsxfrm:: Locale-specific wide-character string transformation
* wcwidth:: Number of column positions of a wide-character code

File: libc.info, Node: wmemchr, Next: wmemcmp, Up: Wchar strings
6.1 `wmemchr'--find a wide character in memory
==============================================
*Synopsis*
#include <wchar.h>
wchar_t *wmemchr(const wchar_t *S, wchar_t C, size_t N);
*Description*
The `wmemchr' function locates the first occurrence of C in the initial
N wide characters of the object pointed to be S. This function is not
affected by locale and all wchar_t values are treated identically. The
null wide character and wchar_t values not corresponding to valid
characters are not treated specially.
If N is zero, S must be a valid pointer and the function behaves as
if no valid occurrence of C is found.
*Returns*
The `wmemchr' function returns a pointer to the located wide character,
or a null pointer if the wide character does not occur in the object.
*Portability*
`wmemchr' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wmemcmp, Next: wmemcpy, Prev: wmemchr, Up: Wchar strings
6.2 `wmemcmp'--compare wide characters in memory
================================================
*Synopsis*
#include <wchar.h>
int wmemcmp(const wchar_t *S1, const wchar_t *S2, size_t N);
*Description*
The `wmemcmp' function compares the first N wide characters of the
object pointed to by S1 to the first N wide characters of the object
pointed to by S2. This function is not affected by locale and all
wchar_t values are treated identically. The null wide character and
wchar_t values not corresponding to valid characters are not treated
specially.
If N is zero, S1 and S2 must be a valid pointers and the function
behaves as if the two objects compare equal.
*Returns*
The `wmemcmp' function returns an integer greater than, equal to, or
less than zero, accordingly as the object pointed to by S1 is greater
than, equal to, or less than the object pointed to by S2.
*Portability*
`wmemcmp' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wmemcpy, Next: wmemmove, Prev: wmemcmp, Up: Wchar strings
6.3 `wmemcpy'--copy wide characters in memory
=============================================
*Synopsis*
#include <wchar.h>
wchar_t *wmemcpy(wchar_t *D, const wchar_t *S, size_t N);
*Description*
The `wmemcpy' function copies N wide characters from the object pointed
to by S to the object pointed to be D. This function is not affected by
locale and all wchar_t values are treated identically. The null wide
character and wchar_t values not corresponding to valid characters are
not treated specially.
If N is zero, D and S must be a valid pointers, and the function
copies zero wide characters.
*Returns*
The `wmemcpy' function returns the value of D.
*Portability*
`wmemcpy' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wmemmove, Next: wmemset, Prev: wmemcpy, Up: Wchar strings
6.4 `wmemmove'--copy wide characters in memory with overlapping areas
=====================================================================
*Synopsis*
#include <wchar.h>
wchar_t *wmemmove(wchar_t *D, const wchar_t *S, size_t N);
*Description*
The `wmemmove' function copies N wide characters from the object
pointed to by S to the object pointed to by D. Copying takes place as
if the N wide characters from the object pointed to by S are first
copied into a temporary array of N wide characters that does not
overlap the objects pointed to by D or S, and then the N wide
characters from the temporary array are copied into the object pointed
to by D.
This function is not affected by locale and all wchar_t values are
treated identically. The null wide character and wchar_t values not
corresponding to valid characters are not treated specially.
If N is zero, D and S must be a valid pointers, and the function
copies zero wide characters.
*Returns*
The `wmemmove' function returns the value of D.
*Portability*
`wmemmove' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wmemset, Next: wcscat, Prev: wmemmove, Up: Wchar strings
6.5 `wmemset'--set wide characters in memory
============================================
*Synopsis*
#include <wchar.h>
wchar_t *wmemset(wchar_t *S, wchar_t C, size_t N);
*Description*
The `wmemset' function copies the value of C into each of the first N
wide characters of the object pointed to by S. This function is not
affected by locale and all wchar_t values are treated identically. The
null wide character and wchar_t values not corresponding to valid
characters are not treated specially.
If N is zero, S must be a valid pointer and the function copies zero
wide characters.
*Returns*
The `wmemset' function returns the value of S.
*Portability*
`wmemset' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcscat, Next: wcschr, Prev: wmemset, Up: Wchar strings
6.6 `wcscat'--concatenate two wide-character strings
====================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcscat(wchar_t *S1, const wchar_t *S2);
*Description*
The `wcscat' function appends a copy of the wide-character string
pointed to by S2 (including the terminating null wide-character code)
to the end of the wide-character string pointed to by S1. The initial
wide-character code of S2 overwrites the null wide-character code at
the end of S1. If copying takes place between objects that overlap, the
behaviour is undefined.
*Returns*
The `wcscat' function returns S1; no return value is reserved to
indicate an error.
*Portability*
`wcscat' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcschr, Next: wcscmp, Prev: wcscat, Up: Wchar strings
6.7 `wcschr'--wide-character string scanning operation
======================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcschr(const wchar_t *S, wchar_t C);
*Description*
The `wcschr' function locates the first occurrence of C in the
wide-character string pointed to by S. The value of C must be a
character representable as a type wchar_t and must be a wide-character
code corresponding to a valid character in the current locale. The
terminating null wide-character string.
*Returns*
Upon completion, `wcschr' returns a pointer to the wide-character code,
or a null pointer if the wide-character code is not found.
*Portability*
`wcschr' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcscmp, Next: wcscoll, Prev: wcschr, Up: Wchar strings
6.8 `wcscmp'--compare two wide-character strings
================================================
*Synopsis*
#include <wchar.h>
int wcscmp(const wchar_t *S1, *S2);
*Description*
The `wcscmp' function compares the wide-character string pointed to by
S1 to the wide-character string pointed to by S2.
The sign of a non-zero return value is determined by the sign of the
difference between the values of the first pair of wide-character codes
that differ in the objects being compared.
*Returns*
Upon completion, `wcscmp' returns an integer greater than, equal to or
less than 0, if the wide-character string pointed to by S1 is greater
than, equal to or less than the wide-character string pointed to by S2
respectively.
*Portability*
`wcscmp' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcscoll, Next: wcscpy, Prev: wcscmp, Up: Wchar strings
6.9 `wcscoll'--locale-specific wide-character string compare
============================================================
*Synopsis*
#include <wchar.h>
int wcscoll(const wchar_t *STRA, const wchar_t * STRB);
*Description*
`wcscoll' compares the wide-character string pointed to by STRA to the
wide-character string pointed to by STRB, using an interpretation
appropriate to the current `LC_COLLATE' state.
The current implementation of `wcscoll' simply uses `wcscmp' and
does not support any language-specific sorting.
*Returns*
If the first string is greater than the second string, `wcscoll'
returns a number greater than zero. If the two strings are equivalent,
`wcscoll' returns zero. If the first string is less than the second
string, `wcscoll' returns a number less than zero.
*Portability*
`wcscoll' is ISO/IEC 9899/AMD1:1995 (ISO C).

File: libc.info, Node: wcscpy, Next: wcpcpy, Prev: wcscoll, Up: Wchar strings
6.10 `wcscpy'--copy a wide-character string
===========================================
*Synopsis*
#include <wchar.h>
wchar_t *wcscpy(wchar_t *S1, const wchar_t *,S2);
*Description*
The `wcscpy' function copies the wide-character string pointed to by S2
(including the terminating null wide-character code) into the array
pointed to by S1. If copying takes place between objects that overlap,
the behaviour is undefined.
*Returns*
The `wcscpy' function returns S1; no return value is reserved to
indicate an error.
*Portability*
`wcscpy' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcpcpy, Next: wcscspn, Prev: wcscpy, Up: Wchar strings
6.11 `wcpcpy'--copy a wide-character string returning a pointer to its end
==========================================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcpcpy(wchar_t *S1, const wchar_t *,S2);
*Description*
The `wcpcpy' function copies the wide-character string pointed to by S2
(including the terminating null wide-character code) into the array
pointed to by S1. If copying takes place between objects that overlap,
the behaviour is undefined.
*Returns*
This function returns a pointer to the end of the destination string,
thus pointing to the trailing '\0'.
*Portability*
`wcpcpy' is a GNU extension.
No supporting OS subroutines are required.

File: libc.info, Node: wcscspn, Next: wcsftime, Prev: wcpcpy, Up: Wchar strings
6.12 `wcscspn'--get length of a complementary wide substring
============================================================
*Synopsis*
#include <wchar.h>
size_t wcscspn(const wchar_t *S, wchar_t *SET);
*Description*
The `wcscspn' function computes the length of the maximum initial
segment of the wide-character string pointed to by S which consists
entirely of wide-character codes not from the wide-character string
pointed to by SET.
*Returns*
The `wcscspn' function returns the length of the initial substring of
S1; no return value is reserved to indicate an error.
*Portability*
`wcscspn' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsftime, Next: wcslcat, Prev: wcscspn, Up: Wchar strings
6.13 `wcsftime'-convert date and time to a formatted wide-character string
==========================================================================
*Synopsis*
#include <time.h>
#include <wchar.h>
size_t wcsftime(wchar_t *S, size_t MAXSIZE,
const wchar_t *FORMAT, const struct tm *TIMP);
*Description*
`wcsftime' is equivalent to `strftime', except that:
* The argument s points to the initial element of an array of wide
characters into which the generated output is to be placed.
* The argument maxsize indicates the limiting number of wide
characters.
* The argument format is a wide-character string and the conversion
specifiers are replaced by corresponding sequences of wide
characters.
* The return value indicates the number of wide characters.
(The difference in all of the above being wide characters versus
regular characters.) See `strftime' for the details of the format
specifiers.
*Returns*
When the formatted time takes up no more than MAXSIZE wide characters,
the result is the length of the formatted wide string. Otherwise, if
the formatting operation was abandoned due to lack of room, the result
is `0', and the wide-character string starting at S corresponds to just
those parts of `*FORMAT' that could be completely filled in within the
MAXSIZE limit.
*Portability*
C99 and POSIX require `wcsftime', but do not specify the contents of
`*S' when the formatted string would require more than MAXSIZE
characters. Unrecognized specifiers and fields of `timp' that are out
of range cause undefined results. Since some formats expand to 0
bytes, it is wise to set `*S' to a nonzero value beforehand to
distinguish between failure and an empty string. This implementation
does not support `s' being NULL, nor overlapping `s' and `format'.
`wcsftime' requires no supporting OS subroutines.
*See Also*
`strftime'

File: libc.info, Node: wcslcat, Next: wcslcpy, Prev: wcsftime, Up: Wchar strings
6.14 `wcslcat'--concatenate wide-character strings to specified length
======================================================================
*Synopsis*
#include <wchar.h>
size_t wcslcat(wchar_t *DST, const wchar_t *SRC, size_t SIZ);
*Description*
The `wcslcat' function appends wide characters from SRC to end of the
DST wide-character string so that the resultant wide-character string
is not more than SIZ wide characters including the terminating null
wide-character code. A terminating null wide character is always added
unless SIZ is 0. Thus, the maximum number of wide characters that can
be appended from SRC is SIZ - 1. If copying takes place between objects
that overlap, the behaviour is undefined.
*Returns*
Wide-character string length of initial DST plus the wide-character
string length of SRC (does not include terminating null
wide-characters). If the return value is greater than or equal to SIZ,
then truncation occurred and not all wide characters from SRC were
appended.
*Portability*
No supporting OS subroutines are required.

File: libc.info, Node: wcslcpy, Next: wcslen, Prev: wcslcat, Up: Wchar strings
6.15 `wcslcpy'--copy a wide-character string to specified length
================================================================
*Synopsis*
#include <wchar.h>
size_t wcslcpy(wchar_t *DST, const wchar_t *SRC, size_t SIZ);
*Description*
`wcslcpy' copies wide characters from SRC to DST such that up to SIZ -
1 characters are copied. A terminating null is appended to the result,
unless SIZ is zero.
*Returns*
`wcslcpy' returns the number of wide characters in SRC, not including
the terminating null wide character. If the return value is greater
than or equal to SIZ, then not all wide characters were copied from SRC
and truncation occurred.
*Portability*
No supporting OS subroutines are required.

File: libc.info, Node: wcslen, Next: wcsncat, Prev: wcslcpy, Up: Wchar strings
6.16 `wcslen'--get wide-character string length
===============================================
*Synopsis*
#include <wchar.h>
size_t wcslen(const wchar_t *S);
*Description*
The `wcslen' function computes the number of wide-character codes in
the wide-character string to which S points, not including the
terminating null wide-character code.
*Returns*
The `wcslen' function returns the length of S; no return value is
reserved to indicate an error.
*Portability*
`wcslen' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsncat, Next: wcsncmp, Prev: wcslen, Up: Wchar strings
6.17 `wcsncat'--concatenate part of two wide-character strings
==============================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcsncat(wchar_t *S1, const wchar_t *S2, size_t N);
*Description*
The `wcsncat' function appends not more than N wide-character codes (a
null wide-character code and wide-character codes that follow it are
not appended) from the array pointed to by S2 to the end of the
wide-character string pointed to by S1. The initial wide-character code
of S2 overwrites the null wide-character code at the end of S1. A
terminating null wide-character code is always appended to the result.
If copying takes place between objects that overlap, the behaviour is
undefined.
*Returns*
The `wcsncat' function returns S1; no return value is reserved to
indicate an error.
*Portability*
`wcsncat' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsncmp, Next: wcsncpy, Prev: wcsncat, Up: Wchar strings
6.18 `wcsncmp'--compare part of two wide-character strings
==========================================================
*Synopsis*
#include <wchar.h>
int wcsncmp(const wchar_t *S1, const wchar_t *S2, size_t N);
*Description*
The `wcsncmp' function compares not more than N wide-character codes
(wide-character codes that follow a null wide-character code are not
compared) from the array pointed to by S1 to the array pointed to by S2.
The sign of a non-zero return value is determined by the sign of the
difference between the values of the first pair of wide-character codes
that differ in the objects being compared.
*Returns*
Upon successful completion, `wcsncmp' returns an integer greater than,
equal to or less than 0, if the possibly null-terminated array pointed
to by S1 is greater than, equal to or less than the possibly
null-terminated array pointed to by S2 respectively.
*Portability*
`wcsncmp' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsncpy, Next: wcpncpy, Prev: wcsncmp, Up: Wchar strings
6.19 `wcsncpy'--copy part of a wide-character string
====================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcsncpy(wchar_t *S1, const wchar_t *S2, size_t N);
*Description*
The `wcsncpy' function copies not more than N wide-character codes
(wide-character codes that follow a null wide-character code are not
copied) from the array pointed to by S2 to the array pointed to by S1.
If copying takes place between objects that overlap, the behaviour is
undefined. Note that if S1 contains more than N wide characters before
its terminating null, the result is not null-terminated.
If the array pointed to by S2 is a wide-character string that is
shorter than N wide-character codes, null wide-character codes are
appended to the copy in the array pointed to by S1, until N
wide-character codes in all are written.
*Returns*
The `wcsncpy' function returns S1; no return value is reserved to
indicate an error.
*Portability*
ISO/IEC 9899; POSIX.1.
No supporting OS subroutines are required.

File: libc.info, Node: wcpncpy, Next: wcsnlen, Prev: wcsncpy, Up: Wchar strings
6.20 `wcpncpy'--copy part of a wide-character string returning a pointer to its end
===================================================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcpncpy(wchar_t *S1, const wchar_t *S2, size_t N);
*Description*
The `wcpncpy' function copies not more than n wide-character codes
(wide-character codes that follow a null wide-character code are not
copied) from the array pointed to by S2 to the array pointed to by S1.
If copying takes place between objects that overlap, the behaviour is
undefined.
If the array pointed to by S2 is a wide-character string that is
shorter than N wide-character codes, null wide-character codes are
appended to the copy in the array pointed to by S1, until N
wide-character codes in all are written.
*Returns*
The `wcpncpy' function returns S1; no return value is reserved to
indicate an error.
*Portability*
`wcpncpy' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsnlen, Next: wcspbrk, Prev: wcpncpy, Up: Wchar strings
6.21 `wcsnlen'--get fixed-size wide-character string length
===========================================================
*Synopsis*
#include <wchar.h>
size_t wcsnlen(const wchar_t *S, size_t MAXLEN);
*Description*
The `wcsnlen' function computes the number of wide-character codes in
the wide-character string pointed to by S not including the terminating
L'\0' wide character but at most MAXLEN wide characters.
*Returns*
`wcsnlen' returns the length of S if it is less then MAXLEN, or MAXLEN
if there is no L'\0' wide character in first MAXLEN characters.
*Portability*
`wcsnlen' is a GNU extension.
`wcsnlen' requires no supporting OS subroutines.

File: libc.info, Node: wcspbrk, Next: wcsrchr, Prev: wcsnlen, Up: Wchar strings
6.22 `wcspbrk'---scan wide-character string for a wide-character code
=====================================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcspbrk(const wchar_t *S, const wchar_t *SET);
*Description*
The `wcspbrk' function locates the first occurrence in the
wide-character string pointed to by S of any wide-character code from
the wide-character string pointed to by SET.
*Returns*
Upon successful completion, `wcspbrk' returns a pointer to the
wide-character code or a null pointer if no wide-character code from
SET occurs in S.
*Portability*
`wcspbrk' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsrchr, Next: wcsspn, Prev: wcspbrk, Up: Wchar strings
6.23 `wcsrchr'--wide-character string scanning operation
========================================================
*Synopsis*
#include <wchar.h>
wchar_t *wcsrchr(const wchar_t *S, wchar_t C);
*Description*
The `wcsrchr' function locates the last occurrence of C in the
wide-character string pointed to by S. The value of C must be a
character representable as a type wchar_t and must be a wide-character
code corresponding to a valid character in the current locale. The
terminating null wide-character code is considered to be part of the
wide-character string.
*Returns*
Upon successful completion, `wcsrchr' returns a pointer to the
wide-character code or a null pointer if C does not occur in the
wide-character string.
*Portability*
`wcsrchr' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsspn, Next: wcsstr, Prev: wcsrchr, Up: Wchar strings
6.24 `wcsspn'--get length of a wide substring
=============================================
*Synopsis*
#include <wchar.h>
size_t wcsspn(const wchar_t *S, const wchar_t *SET);
*Description*
The `wcsspn' function computes the length of the maximum initial
segment of the wide-character string pointed to by S which consists
entirely of wide-character codes from the wide-character string pointed
to by SET.
*Returns*
The wcsspn() function returns the length S1; no return value is
reserved to indicate an error.
*Portability*
`wcsspn' is ISO/IEC 9899/AMD1:1995 (ISO C).
No supporting OS subroutines are required.

File: libc.info, Node: wcsstr, Next: wcstok, Prev: wcsspn, Up: Wchar strings
6.25 `wcsstr'--find a wide-character substring
==============================================
*Synopsis*
#include <wchar.h>
wchar_t *wcsstr(const wchar_t *BIG, const wchar_t *LITTLE);
*Description*
The `wcsstr' function locates the first occurrence in the
wide-character string pointed to by BIG of the sequence of wide
characters (excluding the terminating null wide character) in the
wide-character string pointed to by LITTLE.
*Returns*
On successful completion, `wcsstr' returns a pointer to the located
wide-character string, or a null pointer if the wide-character string
is not found.
If LITTLE points to a wide-character string with zero length, the
function returns BIG.
*Portability*
`wcsstr' is ISO/IEC 9899/AMD1:1995 (ISO C).

File: libc.info, Node: wcstok, Next: wcswidth, Prev: wcsstr, Up: Wchar strings
6.26 `wcstok'--get next token from a string
===========================================
*Synopsis*
#include <wchar.h>
wchar_t *wcstok(wchar_t *SOURCE, const wchar_t *DELIMITERS,
wchar_t **LASTS)
*Description*
The `wcstok' function is the wide-character equivalent of the
`strtok_r' function (which in turn is the same as the `strtok' function
with an added argument to make it thread-safe).
The `wcstok' function is used to isolate (one at a time) sequential
tokens in a null-terminated wide-character string, `*SOURCE'. A token
is defined as a substring not containing any wide-characters from
`*DELIMITERS'.
The first time that `wcstok' is called, `*SOURCE' should be
specified with the wide-character string to be searched, and
`*LASTS'-but not `lasts', which must be non-NULL-may be random;
subsequent calls, wishing to obtain further tokens from the same
string, should pass a null pointer for `*SOURCE' instead but must
supply `*LASTS' unchanged from the last call. The separator
wide-character string, `*DELIMITERS', must be supplied each time and
may change between calls. A pointer to placeholder `*LASTS' must be
supplied by the caller, and is set each time as needed to save the state
by `wcstok'. Every call to `wcstok' with `*SOURCE' == `NULL'
must pass the value of `*LASTS' as last set by `wcstok'.
The `wcstok' function returns a pointer to the beginning of each
subsequent token in the string, after replacing the separator
wide-character itself with a null wide-character. When no more tokens
remain, a null pointer is returned.
*Returns*
`wcstok' returns a pointer to the first wide character of a token, or
`NULL' if there is no token.
*Portability*
`wcstok' is C99 and POSIX.1-2001.
`wcstok' requires no supporting OS subroutines.

File: libc.info, Node: wcswidth, Next: wcsxfrm, Prev: wcstok, Up: Wchar strings
6.27 `wcswidth'--number of column positions of a wide-character string
======================================================================
*Synopsis*
#include <wchar.h>
int wcswidth(const wchar_t *PWCS, size_t N);
*Description*
The `wcswidth' function shall determine the number of column positions
required for N wide-character codes (or fewer than N wide-character
codes if a null wide-character code is encountered before N
wide-character codes are exhausted) in the string pointed to by PWCS.
*Returns*
The `wcswidth' function either shall return 0 (if PWCS points to a null
wide-character code), or return the number of column positions to be
occupied by the wide-character string pointed to by PWCS, or return -1
(if any of the first N wide-character codes in the wide-character
string pointed to by PWCS is not a printable wide-character code).
*Portability*
`wcswidth' has been introduced in the Single UNIX Specification Volume
2. `wcswidth' has been marked as an extension in the Single UNIX
Specification Volume 3.

File: libc.info, Node: wcsxfrm, Next: wcwidth, Prev: wcswidth, Up: Wchar strings
6.28 `wcsxfrm'--locale-specific wide-character string transformation
====================================================================
*Synopsis*
#include <wchar.h>
int wcsxfrm(wchar_t *STRA, const wchar_t * STRB, size_t N);
*Description*
`wcsxfrm' transforms the wide-character string pointed to by STRB to
the wide-character string pointed to by STRA, Comparing two transformed
wide strings with `wcscmp' should return the same result as comparing
the original strings with `wcscoll'. No more than N wide characters
are transformed, including the trailing null character.
If N is 0, STRA may be a NULL pointer.
The current implementation of `wcsxfrm' simply uses `wcslcpy' and
does not support any language-specific transformations.
*Returns*
`wcsxfrm' returns the length of the transformed wide character string.
if the return value is greater or equal to N, the content of STRA is
undefined.
*Portability*
`wcsxfrm' is ISO/IEC 9899/AMD1:1995 (ISO C).

File: libc.info, Node: wcwidth, Prev: wcsxfrm, Up: Wchar strings
6.29 `wcwidth'--number of column positions of a wide-character code
===================================================================
*Synopsis*
#include <wchar.h>
int wcwidth(const wchar_t WC);
*Description*
The `wcwidth' function shall determine the number of column positions
required for the wide character WC. The application shall ensure that
the value of WC is a character representable as a wchar_t, and is a
wide-character code corresponding to a valid character in the current
locale.
*Returns*
The `wcwidth' function shall either return 0 (if WC is a null
wide-character code), or return the number of column positions to be
occupied by the wide-character code WC, or return -1 (if WC does not
correspond to a printable wide-character code).
*Portability*
`wcwidth' has been introduced in the Single UNIX Specification Volume 2.
`wcwidth' has been marked as an extension in the Single UNIX
Specification Volume 3.

File: libc.info, Node: Signals, Next: Timefns, Prev: Wchar strings, Up: Top
7 Signal Handling (`signal.h')
******************************
A "signal" is an event that interrupts the normal flow of control in
your program. Your operating environment normally defines the full set
of signals available (see `sys/signal.h'), as well as the default means
of dealing with them--typically, either printing an error message and
aborting your program, or ignoring the signal.
All systems support at least the following signals:
`SIGABRT'
Abnormal termination of a program; raised by the <<abort>>
function.
`SIGFPE'
A domain error in arithmetic, such as overflow, or division by
zero.
`SIGILL'
Attempt to execute as a function data that is not executable.
`SIGINT'
Interrupt; an interactive attention signal.
`SIGSEGV'
An attempt to access a memory location that is not available.
`SIGTERM'
A request that your program end execution.
Two functions are available for dealing with asynchronous
signals--one to allow your program to send signals to itself (this is
called "raising" a signal), and one to specify subroutines (called
"handlers" to handle particular signals that you anticipate may
occur--whether raised by your own program or the operating environment.
To support these functions, `signal.h' defines three macros:
`SIG_DFL'
Used with the `signal' function in place of a pointer to a handler
subroutine, to select the operating environment's default handling
of a signal.
`SIG_IGN'
Used with the `signal' function in place of a pointer to a
handler, to ignore a particular signal.
`SIG_ERR'
Returned by the `signal' function in place of a pointer to a
handler, to indicate that your request to set up a handler could
not be honored for some reason.
`signal.h' also defines an integral type, `sig_atomic_t'. This type
is not used in any function declarations; it exists only to allow your
signal handlers to declare a static storage location where they may
store a signal value. (Static storage is not otherwise reliable from
signal handlers.)
* Menu:
* psignal:: Print a signal message to standard error
* raise:: Send a signal
* signal:: Specify handler subroutine for a signal

File: libc.info, Node: psignal, Next: raise, Up: Signals
7.1 `psignal'--print a signal message on standard error
=======================================================
*Synopsis*
#include <stdio.h>
void psignal(int SIGNAL, const char *PREFIX);
*Description*
Use `psignal' to print (on standard error) a signal message
corresponding to the value of the signal number SIGNAL. Unless you use
`NULL' as the value of the argument PREFIX, the signal message will
begin with the string at PREFIX, followed by a colon and a space (`:
'). The remainder of the signal message is one of the strings described
for `strsignal'.
*Returns*
`psignal' returns no result.
*Portability*
POSIX.1-2008 requires `psignal', but the strings issued vary from one
implementation to another.
Supporting OS subroutines required: `close', `fstat', `isatty',
`lseek', `read', `sbrk', `write'.

File: libc.info, Node: raise, Next: signal, Prev: psignal, Up: Signals
7.2 `raise'--send a signal
==========================
*Synopsis*
#include <signal.h>
int raise(int SIG);
int _raise_r(void *REENT, int SIG);
*Description*
Send the signal SIG (one of the macros from ``sys/signal.h''). This
interrupts your program's normal flow of execution, and allows a signal
handler (if you've defined one, using `signal') to take control.
The alternate function `_raise_r' is a reentrant version. The extra
argument REENT is a pointer to a reentrancy structure.
*Returns*
The result is `0' if SIG was successfully raised, `1' otherwise.
However, the return value (since it depends on the normal flow of
execution) may not be visible, unless the signal handler for SIG
terminates with a `return' or unless `SIG_IGN' is in effect for this
signal.
*Portability*
ANSI C requires `raise', but allows the full set of signal numbers to
vary from one implementation to another.
Required OS subroutines: `getpid', `kill'.

File: libc.info, Node: signal, Prev: raise, Up: Signals
7.3 `signal'--specify handler subroutine for a signal
=====================================================
*Synopsis*
#include <signal.h>
void (*signal(int SIG, void(*FUNC)(int))) (int);
void (*_signal_r(void *REENT, int SIG, void(*FUNC)(int))) (int);
*Description*
`signal' provides a simple signal-handling implementation for embedded
targets.
`signal' allows you to request changed treatment for a particular
signal SIG. You can use one of the predefined macros `SIG_DFL' (select
system default handling) or `SIG_IGN' (ignore this signal) as the value
of FUNC; otherwise, FUNC is a function pointer that identifies a
subroutine in your program as the handler for this signal.
Some of the execution environment for signal handlers is
unpredictable; notably, the only library function required to work
correctly from within a signal handler is `signal' itself, and only
when used to redefine the handler for the current signal value.
Static storage is likewise unreliable for signal handlers, with one
exception: if you declare a static storage location as ``volatile
sig_atomic_t'', then you may use that location in a signal handler to
store signal values.
If your signal handler terminates using `return' (or implicit
return), your program's execution continues at the point where it was
when the signal was raised (whether by your program itself, or by an
external event). Signal handlers can also use functions such as `exit'
and `abort' to avoid returning.
The alternate function `_signal_r' is the reentrant version. The
extra argument REENT is a pointer to a reentrancy structure.
*Returns*
If your request for a signal handler cannot be honored, the result is
`SIG_ERR'; a specific error number is also recorded in `errno'.
Otherwise, the result is the previous handler (a function pointer or
one of the predefined macros).
*Portability*
ANSI C requires `signal'.
No supporting OS subroutines are required to link with `signal', but
it will not have any useful effects, except for software generated
signals, without an operating system that can actually raise exceptions.

File: libc.info, Node: Timefns, Next: Locale, Prev: Signals, Up: Top
8 Time Functions (`time.h')
***************************
This chapter groups functions used either for reporting on time
(elapsed, current, or compute time) or to perform calculations based on
time.
The header file `time.h' defines three types. `clock_t' and
`time_t' are both used for representations of time particularly
suitable for arithmetic. (In this implementation, quantities of type
`clock_t' have the highest resolution possible on your machine, and
quantities of type `time_t' resolve to seconds.) `size_t' is also
defined if necessary for quantities representing sizes.
`time.h' also defines the structure `tm' for the traditional
representation of Gregorian calendar time as a series of numbers, with
the following fields:
`tm_sec'
Seconds, between 0 and 60 inclusive (60 allows for leap seconds).
`tm_min'
Minutes, between 0 and 59 inclusive.
`tm_hour'
Hours, between 0 and 23 inclusive.
`tm_mday'
Day of the month, between 1 and 31 inclusive.
`tm_mon'
Month, between 0 (January) and 11 (December).
`tm_year'
Year (since 1900), can be negative for earlier years.
`tm_wday'
Day of week, between 0 (Sunday) and 6 (Saturday).
`tm_yday'
Number of days elapsed since last January 1, between 0 and 365
inclusive.
`tm_isdst'
Daylight Savings Time flag: positive means DST in effect, zero
means DST not in effect, negative means no information about DST
is available. Although for mktime(), negative means that it
should decide if DST is in effect or not.
* Menu:
* asctime:: Format time as string
* clock:: Cumulative processor time
* ctime:: Convert time to local and format as string
* difftime:: Subtract two times
* gmtime:: Convert time to UTC (GMT) traditional representation
* localtime:: Convert time to local representation
* mktime:: Convert time to arithmetic representation
* strftime:: Convert date and time to a user-formatted string
* time:: Get current calendar time (as single number)
* __tz_lock:: Lock time zone global variables
* tzset:: Set timezone info

File: libc.info, Node: asctime, Next: clock, Up: Timefns
8.1 `asctime'--format time as string
====================================
*Synopsis*
#include <time.h>
char *asctime(const struct tm *CLOCK);
char *_asctime_r(const struct tm *CLOCK, char *BUF);
*Description*
Format the time value at CLOCK into a string of the form
Wed Jun 15 11:38:07 1988\n\0
The string is generated in a static buffer; each call to `asctime'
overwrites the string generated by previous calls.
*Returns*
A pointer to the string containing a formatted timestamp.
*Portability*
ANSI C requires `asctime'.
`asctime' requires no supporting OS subroutines.

File: libc.info, Node: clock, Next: ctime, Prev: asctime, Up: Timefns
8.2 `clock'--cumulative processor time
======================================
*Synopsis*
#include <time.h>
clock_t clock(void);
*Description*
Calculates the best available approximation of the cumulative amount of
time used by your program since it started. To convert the result into
seconds, divide by the macro `CLOCKS_PER_SEC'.
*Returns*
The amount of processor time used so far by your program, in units
defined by the machine-dependent macro `CLOCKS_PER_SEC'. If no
measurement is available, the result is (clock_t)`-1'.
*Portability*
ANSI C requires `clock' and `CLOCKS_PER_SEC'.
Supporting OS subroutine required: `times'.

File: libc.info, Node: ctime, Next: difftime, Prev: clock, Up: Timefns
8.3 `ctime'--convert time to local and format as string
=======================================================
*Synopsis*
#include <time.h>
char *ctime(const time_t *CLOCK);
char *ctime_r(const time_t *CLOCK, char *BUF);
*Description*
Convert the time value at CLOCK to local time (like `localtime') and
format it into a string of the form
Wed Jun 15 11:38:07 1988\n\0
(like `asctime').
*Returns*
A pointer to the string containing a formatted timestamp.
*Portability*
ANSI C requires `ctime'.
`ctime' requires no supporting OS subroutines.

File: libc.info, Node: difftime, Next: gmtime, Prev: ctime, Up: Timefns
8.4 `difftime'--subtract two times
==================================
*Synopsis*
#include <time.h>
double difftime(time_t TIM1, time_t TIM2);
*Description*
Subtracts the two times in the arguments: ``TIM1 - TIM2''.
*Returns*
The difference (in seconds) between TIM2 and TIM1, as a `double'.
*Portability*
ANSI C requires `difftime', and defines its result to be in seconds in
all implementations.
`difftime' requires no supporting OS subroutines.

File: libc.info, Node: gmtime, Next: localtime, Prev: difftime, Up: Timefns
8.5 `gmtime'--convert time to UTC traditional form
==================================================
*Synopsis*
#include <time.h>
struct tm *gmtime(const time_t *CLOCK);
struct tm *gmtime_r(const time_t *CLOCK, struct tm *RES);
*Description*
`gmtime' takes the time at CLOCK representing the number of elapsed
seconds since 00:00:00 on January 1, 1970, Universal Coordinated Time
(UTC, also known in some countries as GMT, Greenwich Mean time) and
converts it to a `struct tm' representation.
`gmtime' constructs the traditional time representation in static
storage; each call to `gmtime' or `localtime' will overwrite the
information generated by previous calls to either function.
*Returns*
A pointer to the traditional time representation (`struct tm').
*Portability*
ANSI C requires `gmtime'.
`gmtime' requires no supporting OS subroutines.

File: libc.info, Node: localtime, Next: mktime, Prev: gmtime, Up: Timefns
8.6 `localtime'--convert time to local representation
=====================================================
*Synopsis*
#include <time.h>
struct tm *localtime(time_t *CLOCK);
struct tm *localtime_r(time_t *CLOCK, struct tm *RES);
*Description*
`localtime' converts the time at CLOCK into local time, then converts
its representation from the arithmetic representation to the
traditional representation defined by `struct tm'.
`localtime' constructs the traditional time representation in static
storage; each call to `gmtime' or `localtime' will overwrite the
information generated by previous calls to either function.
`mktime' is the inverse of `localtime'.
*Returns*
A pointer to the traditional time representation (`struct tm').
*Portability*
ANSI C requires `localtime'.
`localtime' requires no supporting OS subroutines.

File: libc.info, Node: mktime, Next: strftime, Prev: localtime, Up: Timefns
8.7 `mktime'--convert time to arithmetic representation
=======================================================
*Synopsis*
#include <time.h>
time_t mktime(struct tm *TIMP);
*Description*
`mktime' assumes the time at TIMP is a local time, and converts its
representation from the traditional representation defined by `struct
tm' into a representation suitable for arithmetic.
`localtime' is the inverse of `mktime'.
*Returns*
If the contents of the structure at TIMP do not form a valid calendar
time representation, the result is `-1'. Otherwise, the result is the
time, converted to a `time_t' value.
*Portability*
ANSI C requires `mktime'.
`mktime' requires no supporting OS subroutines.

File: libc.info, Node: strftime, Next: time, Prev: mktime, Up: Timefns
8.8 `strftime'--convert date and time to a formatted string
===========================================================
*Synopsis*
#include <time.h>
size_t strftime(char *S, size_t MAXSIZE,
const char *FORMAT, const struct tm *TIMP);
*Description*
`strftime' converts a `struct tm' representation of the time (at TIMP)
into a null-terminated string, starting at S and occupying no more than
MAXSIZE characters.
You control the format of the output using the string at FORMAT.
`*FORMAT' can contain two kinds of specifications: text to be copied
literally into the formatted string, and time conversion
specifications. Time conversion specifications are two- and
three-character sequences beginning with ``%'' (use ``%%'' to include a
percent sign in the output). Each defined conversion specification
selects only the specified field(s) of calendar time data from `*TIMP',
and converts it to a string in one of the following ways:
`%a'
The abbreviated weekday name according to the current locale.
[tm_wday]
`%A'
The full weekday name according to the current locale. In the
default "C" locale, one of ``Sunday'', ``Monday'', ``Tuesday'',
``Wednesday'', ``Thursday'', ``Friday'', ``Saturday''. [tm_wday]
`%b'
The abbreviated month name according to the current locale.
[tm_mon]
`%B'
The full month name according to the current locale. In the
default "C" locale, one of ``January'', ``February'', ``March'',
``April'', ``May'', ``June'', ``July'', ``August'', ``September'',
``October'', ``November'', ``December''. [tm_mon]
`%c'
The preferred date and time representation for the current locale.
[tm_sec, tm_min, tm_hour, tm_mday, tm_mon, tm_year, tm_wday]
`%C'
The century, that is, the year divided by 100 then truncated. For
4-digit years, the result is zero-padded and exactly two
characters; but for other years, there may a negative sign or more
digits. In this way, ``%C%y'' is equivalent to ``%Y''. [tm_year]
`%d'
The day of the month, formatted with two digits (from ``01'' to
``31''). [tm_mday]
`%D'
A string representing the date, in the form ``"%m/%d/%y"''.
[tm_mday, tm_mon, tm_year]
`%e'
The day of the month, formatted with leading space if single digit
(from ``1'' to ``31''). [tm_mday]
`%E`x''
In some locales, the E modifier selects alternative
representations of certain modifiers `x'. In newlib, it is
ignored, and treated as %`x'.
`%F'
A string representing the ISO 8601:2000 date format, in the form
``"%Y-%m-%d"''. [tm_mday, tm_mon, tm_year]
`%g'
The last two digits of the week-based year, see specifier %G (from
``00'' to ``99''). [tm_year, tm_wday, tm_yday]
`%G'
The week-based year. In the ISO 8601:2000 calendar, week 1 of the
year includes January 4th, and begin on Mondays. Therefore, if
January 1st, 2nd, or 3rd falls on a Sunday, that day and earlier
belong to the last week of the previous year; and if December
29th, 30th, or 31st falls on Monday, that day and later belong to
week 1 of the next year. For consistency with %Y, it always has
at least four characters. Example: "%G" for Saturday 2nd January
1999 gives "1998", and for Tuesday 30th December 1997 gives
"1998". [tm_year, tm_wday, tm_yday]
`%h'
Synonym for "%b". [tm_mon]
`%H'
The hour (on a 24-hour clock), formatted with two digits (from
``00'' to ``23''). [tm_hour]
`%I'
The hour (on a 12-hour clock), formatted with two digits (from
``01'' to ``12''). [tm_hour]
`%j'
The count of days in the year, formatted with three digits (from
``001'' to ``366''). [tm_yday]
`%k'
The hour (on a 24-hour clock), formatted with leading space if
single digit (from ``0'' to ``23''). Non-POSIX extension (c.p.
%I). [tm_hour]
`%l'
The hour (on a 12-hour clock), formatted with leading space if
single digit (from ``1'' to ``12''). Non-POSIX extension (c.p.
%H). [tm_hour]
`%m'
The month number, formatted with two digits (from ``01'' to
``12''). [tm_mon]
`%M'
The minute, formatted with two digits (from ``00'' to ``59'').
[tm_min]
`%n'
A newline character (``\n'').
`%O`x''
In some locales, the O modifier selects alternative digit
characters for certain modifiers `x'. In newlib, it is ignored,
and treated as %`x'.
`%p'
Either ``AM'' or ``PM'' as appropriate, or the corresponding
strings for the current locale. [tm_hour]
`%P'
Same as '`%p'', but in lowercase. This is a GNU extension.
[tm_hour]
`%r'
Replaced by the time in a.m. and p.m. notation. In the "C" locale
this is equivalent to "%I:%M:%S %p". In locales which don't
define a.m./p.m. notations, the result is an empty string.
[tm_sec, tm_min, tm_hour]
`%R'
The 24-hour time, to the minute. Equivalent to "%H:%M". [tm_min,
tm_hour]
`%S'
The second, formatted with two digits (from ``00'' to ``60''). The
value 60 accounts for the occasional leap second. [tm_sec]
`%t'
A tab character (``\t'').
`%T'
The 24-hour time, to the second. Equivalent to "%H:%M:%S".
[tm_sec, tm_min, tm_hour]
`%u'
The weekday as a number, 1-based from Monday (from ``1'' to
``7''). [tm_wday]
`%U'
The week number, where weeks start on Sunday, week 1 contains the
first Sunday in a year, and earlier days are in week 0. Formatted
with two digits (from ``00'' to ``53''). See also `%W'. [tm_wday,
tm_yday]
`%V'
The week number, where weeks start on Monday, week 1 contains
January 4th, and earlier days are in the previous year. Formatted
with two digits (from ``01'' to ``53''). See also `%G'. [tm_year,
tm_wday, tm_yday]
`%w'
The weekday as a number, 0-based from Sunday (from ``0'' to ``6'').
[tm_wday]
`%W'
The week number, where weeks start on Monday, week 1 contains the
first Monday in a year, and earlier days are in week 0. Formatted
with two digits (from ``00'' to ``53''). [tm_wday, tm_yday]
`%x'
Replaced by the preferred date representation in the current
locale. In the "C" locale this is equivalent to "%m/%d/%y".
[tm_mon, tm_mday, tm_year]
`%X'
Replaced by the preferred time representation in the current
locale. In the "C" locale this is equivalent to "%H:%M:%S".
[tm_sec, tm_min, tm_hour]
`%y'
The last two digits of the year (from ``00'' to ``99''). [tm_year]
(Implementation interpretation: always positive, even for
negative years.)
`%Y'
The full year, equivalent to `%C%y'. It will always have at least
four characters, but may have more. The year is accurate even
when tm_year added to the offset of 1900 overflows an int.
[tm_year]
`%z'
The offset from UTC. The format consists of a sign (negative is
west of Greewich), two characters for hour, then two characters
for minutes (-hhmm or +hhmm). If tm_isdst is negative, the offset
is unknown and no output is generated; if it is zero, the offset
is the standard offset for the current time zone; and if it is
positive, the offset is the daylight savings offset for the
current timezone. The offset is determined from the TZ environment
variable, as if by calling tzset(). [tm_isdst]
`%Z'
The time zone name. If tm_isdst is negative, no output is
generated. Otherwise, the time zone name is based on the TZ
environment variable, as if by calling tzset(). [tm_isdst]
`%%'
A single character, ``%''.
*Returns*
When the formatted time takes up no more than MAXSIZE characters, the
result is the length of the formatted string. Otherwise, if the
formatting operation was abandoned due to lack of room, the result is
`0', and the string starting at S corresponds to just those parts of
`*FORMAT' that could be completely filled in within the MAXSIZE limit.
*Portability*
ANSI C requires `strftime', but does not specify the contents of `*S'
when the formatted string would require more than MAXSIZE characters.
Unrecognized specifiers and fields of `timp' that are out of range
cause undefined results. Since some formats expand to 0 bytes, it is
wise to set `*S' to a nonzero value beforehand to distinguish between
failure and an empty string. This implementation does not support `s'
being NULL, nor overlapping `s' and `format'.
`strftime' requires no supporting OS subroutines.
*Bugs*
`strftime' ignores the LC_TIME category of the current locale,
hard-coding the "C" locale settings.

File: libc.info, Node: time, Next: __tz_lock, Prev: strftime, Up: Timefns
8.9 `time'--get current calendar time (as single number)
========================================================
*Synopsis*
#include <time.h>
time_t time(time_t *T);
*Description*
`time' looks up the best available representation of the current time
and returns it, encoded as a `time_t'. It stores the same value at T
unless the argument is `NULL'.
*Returns*
A `-1' result means the current time is not available; otherwise the
result represents the current time.
*Portability*
ANSI C requires `time'.
Supporting OS subroutine required: Some implementations require
`gettimeofday'.

File: libc.info, Node: __tz_lock, Next: tzset, Prev: time, Up: Timefns
8.10 `__tz_lock', `__tz_unlock'--lock time zone global variables
================================================================
*Synopsis*
#include "local.h"
void __tz_lock (void);
void __tz_unlock (void);
*Description*
The `tzset' facility functions call these functions when they need to
ensure the values of global variables. The version of these routines
supplied in the library use the lock API defined in sys/lock.h. If
multiple threads of execution can call the time functions and give up
scheduling in the middle, then you you need to define your own versions
of these functions in order to safely lock the time zone variables
during a call. If you do not, the results of `localtime', `mktime',
`ctime', and `strftime' are undefined.
The lock `__tz_lock' may not be called recursively; that is, a call
`__tz_lock' will always lock all subsequent `__tz_lock' calls until the
corresponding `__tz_unlock' call on the same thread is made.

File: libc.info, Node: tzset, Prev: __tz_lock, Up: Timefns
8.11 `tzset'--set timezone characteristics from TZ environment variable
=======================================================================
*Synopsis*
#include <time.h>
void tzset(void);
void _tzset_r (struct _reent *);
*Description*
`tzset' examines the TZ environment variable and sets up the three
external variables: `_timezone', `_daylight', and `tzname'. The value
of `_timezone' shall be the offset from the current time zone to GMT.
The value of `_daylight' shall be 0 if there is no daylight savings
time for the current time zone, otherwise it will be non-zero. The
`tzname' array has two entries: the first is the name of the standard
time zone, the second is the name of the daylight-savings time zone.
The TZ environment variable is expected to be in the following POSIX
format:
stdoffset1[dst[offset2][,start[/time1],end[/time2]]]
where: std is the name of the standard time-zone (minimum 3 chars)
offset1 is the value to add to local time to arrive at Universal time
it has the form: hh[:mm[:ss]] dst is the name of the alternate
(daylight-savings) time-zone (min 3 chars) offset2 is the value to add
to local time to arrive at Universal time it has the same format as the
std offset start is the day that the alternate time-zone starts time1
is the optional time that the alternate time-zone starts (this is in
local time and defaults to 02:00:00 if not specified) end is the day
that the alternate time-zone ends time2 is the time that the alternate
time-zone ends (it is in local time and defaults to 02:00:00 if not
specified)
Note that there is no white-space padding between fields. Also note
that if TZ is null, the default is Universal GMT which has no
daylight-savings time. If TZ is empty, the default EST5EDT is used.
The function `_tzset_r' is identical to `tzset' only it is reentrant
and is used for applications that use multiple threads.
*Returns*
There is no return value.
*Portability*
`tzset' is part of the POSIX standard.
Supporting OS subroutine required: None

File: libc.info, Node: Locale, Next: Reentrancy, Prev: Timefns, Up: Top
9 Locale (`locale.h')
*********************
A "locale" is the name for a collection of parameters (affecting
collating sequences and formatting conventions) that may be different
depending on location or culture. The `"C"' locale is the only one
defined in the ANSI C standard.
This is a minimal implementation, supporting only the required `"C"'
value for locale; strings representing other locales are not honored.
(`""' is also accepted; it represents the default locale for an
implementation, here equivalent to `"C"'.
`locale.h' defines the structure `lconv' to collect the information
on a locale, with the following fields:
`char *decimal_point'
The decimal point character used to format "ordinary" numbers (all
numbers except those referring to amounts of money). `"."' in the
C locale.
`char *thousands_sep'
The character (if any) used to separate groups of digits, when
formatting ordinary numbers. `""' in the C locale.
`char *grouping'
Specifications for how many digits to group (if any grouping is
done at all) when formatting ordinary numbers. The _numeric
value_ of each character in the string represents the number of
digits for the next group, and a value of `0' (that is, the
string's trailing `NULL') means to continue grouping digits using
the last value specified. Use `CHAR_MAX' to indicate that no
further grouping is desired. `""' in the C locale.
`char *int_curr_symbol'
The international currency symbol (first three characters), if
any, and the character used to separate it from numbers. `""' in
the C locale.
`char *currency_symbol'
The local currency symbol, if any. `""' in the C locale.
`char *mon_decimal_point'
The symbol used to delimit fractions in amounts of money. `""' in
the C locale.
`char *mon_thousands_sep'
Similar to `thousands_sep', but used for amounts of money. `""'
in the C locale.
`char *mon_grouping'
Similar to `grouping', but used for amounts of money. `""' in the
C locale.
`char *positive_sign'
A string to flag positive amounts of money when formatting. `""'
in the C locale.
`char *negative_sign'
A string to flag negative amounts of money when formatting. `""'
in the C locale.
`char int_frac_digits'
The number of digits to display when formatting amounts of money to
international conventions. `CHAR_MAX' (the largest number
representable as a `char') in the C locale.
`char frac_digits'
The number of digits to display when formatting amounts of money to
local conventions. `CHAR_MAX' in the C locale.
`char p_cs_precedes'
`1' indicates the local currency symbol is used before a _positive
or zero_ formatted amount of money; `0' indicates the currency
symbol is placed after the formatted number. `CHAR_MAX' in the C
locale.
`char p_sep_by_space'
`1' indicates the local currency symbol must be separated from
_positive or zero_ numbers by a space; `0' indicates that it is
immediately adjacent to numbers. `CHAR_MAX' in the C locale.
`char n_cs_precedes'
`1' indicates the local currency symbol is used before a
_negative_ formatted amount of money; `0' indicates the currency
symbol is placed after the formatted number. `CHAR_MAX' in the C
locale.
`char n_sep_by_space'
`1' indicates the local currency symbol must be separated from
_negative_ numbers by a space; `0' indicates that it is
immediately adjacent to numbers. `CHAR_MAX' in the C locale.
`char p_sign_posn'
Controls the position of the _positive_ sign for numbers
representing money. `0' means parentheses surround the number;
`1' means the sign is placed before both the number and the
currency symbol; `2' means the sign is placed after both the number
and the currency symbol; `3' means the sign is placed just before
the currency symbol; and `4' means the sign is placed just after
the currency symbol. `CHAR_MAX' in the C locale.
`char n_sign_posn'
Controls the position of the _negative_ sign for numbers
representing money, using the same rules as `p_sign_posn'.
`CHAR_MAX' in the C locale.
* Menu:
* setlocale:: Select or query locale

File: libc.info, Node: setlocale, Up: Locale
9.1 `setlocale', `localeconv'--select or query locale
=====================================================
*Synopsis*
#include <locale.h>
char *setlocale(int CATEGORY, const char *LOCALE);
lconv *localeconv(void);
char *_setlocale_r(void *REENT,
int CATEGORY, const char *LOCALE);
lconv *_localeconv_r(void *REENT);
*Description*
`setlocale' is the facility defined by ANSI C to condition the
execution environment for international collating and formatting
information; `localeconv' reports on the settings of the current locale.
This is a minimal implementation, supporting only the required
`"POSIX"' and `"C"' values for LOCALE; strings representing other
locales are not honored unless _MB_CAPABLE is defined.
If _MB_CAPABLE is defined, POSIX locale strings are allowed,
following the form
language[_TERRITORY][.charset][@modifier]
`"language"' is a two character string per ISO 639, or, if not
available for a given language, a three character string per ISO 639-3.
`"TERRITORY"' is a country code per ISO 3166. For `"charset"' and
`"modifier"' see below.
Additionally to the POSIX specifier, the following extension is
supported for backward compatibility with older implementations using
newlib: `"C-charset"'. Instead of `"C-"', you can also specify `"C."'.
Both variations allow to specify language neutral locales while using
other charsets than ASCII, for instance `"C.UTF-8"', which keeps all
settings as in the C locale, but uses the UTF-8 charset.
The following charsets are recognized: `"UTF-8"', `"JIS"',
`"EUCJP"', `"SJIS"', `"KOI8-R"', `"KOI8-U"', `"GEORGIAN-PS"',
`"PT154"', `"TIS-620"', `"ISO-8859-x"' with 1 <= x <= 16, or `"CPxxx"'
with xxx in [437, 720, 737, 775, 850, 852, 855, 857, 858, 862, 866,
874, 932, 1125, 1250, 1251, 1252, 1253, 1254, 1255, 1256, 1257, 1258].
Charsets are case insensitive. For instance, `"EUCJP"' and `"eucJP"'
are equivalent. Charset names with dashes can also be written without
dashes, as in `"UTF8"', `"iso88591"' or `"koi8r"'. `"EUCJP"' and
`"EUCKR"' are also recognized with dash, `"EUC-JP"' and `"EUC-KR"'.
Full support for all of the above charsets requires that newlib has
been build with multibyte support and support for all ISO and Windows
Codepage. Otherwise all singlebyte charsets are simply mapped to
ASCII. Right now, only newlib for Cygwin is built with full charset
support by default. Under Cygwin, this implementation additionally
supports the charsets `"GBK"', `"GB2312"', `"eucCN"', `"eucKR"', and
`"Big5"'. Cygwin does not support `"JIS"'.
Cygwin additionally supports locales from the file
/usr/share/locale/locale.alias.
(`""' is also accepted; if given, the settings are read from the
corresponding LC_* environment variables and $LANG according to POSIX
rules.
This implementation also supports the modifier `"cjknarrow"', which
affects how the functions `wcwidth' and `wcswidth' handle characters
from the "CJK Ambiguous Width" category of characters described at
http://www.unicode.org/reports/tr11/#Ambiguous. These characters have a
width of 1 for singlebyte charsets and a width of 2 for multibyte
charsets other than UTF-8. For UTF-8, their width depends on the
language specifier: it is 2 for `"zh"' (Chinese), `"ja"' (Japanese),
and `"ko"' (Korean), and 1 for everything else. Specifying
`"cjknarrow"' forces a width of 1, independent of charset and language.
If you use `NULL' as the LOCALE argument, `setlocale' returns a
pointer to the string representing the current locale. The acceptable
values for CATEGORY are defined in ``locale.h'' as macros beginning
with `"LC_"'.
`localeconv' returns a pointer to a structure (also defined in
``locale.h'') describing the locale-specific conventions currently in
effect.
`_localeconv_r' and `_setlocale_r' are reentrant versions of
`localeconv' and `setlocale' respectively. The extra argument REENT is
a pointer to a reentrancy structure.
*Returns*
A successful call to `setlocale' returns a pointer to a string
associated with the specified category for the new locale. The string
returned by `setlocale' is such that a subsequent call using that
string will restore that category (or all categories in case of LC_ALL),
to that state. The application shall not modify the string returned
which may be overwritten by a subsequent call to `setlocale'. On
error, `setlocale' returns `NULL'.
`localeconv' returns a pointer to a structure of type `lconv', which
describes the formatting and collating conventions in effect (in this
implementation, always those of the C locale).
*Portability*
ANSI C requires `setlocale', but the only locale required across all
implementations is the C locale.

File: libc.info, Node: Reentrancy, Next: Misc, Prev: Locale, Up: Top
10 Reentrancy
*************
Reentrancy is a characteristic of functions which allows them to be
safely called recursively or from concurrent processes. Libraries of
reentrant functions enable multiple processes to use the same address
space with assurance that the values stored in those spaces will remain
constant between calls. A fully reentrant library function does not
access any resources that could be shared with another concurrent or
recursive invocation of that function. The reentrancy features
described here provide a mechanism for each process to have separate
resources.
A system with multiple threads may share resources such as the heap,
environment, file pointers, writable static data, or devices. Any
library function that deals with such shared resources cannot be fully
reentrant. If you want to share resources across threads, you may need
a mechanism such as locking to protect access to them and make the
relevant functions thread-safe. See the `Xtensa Linker Support
Packages (LSPs) Reference Manual' for more information about reentrancy
and thread safety.
The Red Hat newlib implementation of the library functions ensures
that whenever possible, these library functions are reentrant. However,
there are some functions that can not be trivially made reentrant.
Hooks have been provided to allow you to use these functions in a fully
reentrant fashion.
These hooks use the structure `_reent' defined in `reent.h'. A
variable defined as `struct _reent' is called a "reentrancy structure".
All functions which must manipulate global information are available
in two versions. The first version has the usual name, and uses a
single global instance of the reentrancy structure. The second has a
different name, normally formed by prepending `_' and appending `_r',
and takes a pointer to the particular reentrancy structure to use.
For example, the function `fopen' takes two arguments, FILE and
MODE, and uses the global reentrancy structure. The function
`_fopen_r' takes the arguments, STRUCT_REENT, which is a pointer to an
instance of the reentrancy structure, FILE and MODE.
There are two versions of `struct _reent', a normal one and one for
small memory systems, controlled by the `_REENT_SMALL' definition from
the (automatically included) `<sys/config.h>'.
Each function which uses the global reentrancy structure uses the
global variable `_impure_ptr', which points to a reentrancy structure.
This means that you have two ways to achieve reentrancy. Both
require that each thread of execution control initialize a unique global
variable of type `struct _reent':
1. Use the reentrant versions of the library functions, after
initializing a global reentrancy structure for each process. Use
the pointer to this structure as the extra argument for all
library functions.
2. Ensure that each thread of execution control has a pointer to its
own unique reentrancy structure in the global variable
`_impure_ptr', and call the standard library subroutines.
The following functions are provided in both reentrant and
non-reentrant versions.
_Equivalent for errno variable:_
_errno_r
_Locale functions:_
_localeconv_r _setlocale_r
_Equivalents for stdio variables:_
_stdin_r _stdout_r _stderr_r
_Stdio functions:_
_fdopen_r _perror_r _tempnam_r
_fopen_r _putchar_r _tmpnam_r
_getchar_r _puts_r _tmpfile_r
_gets_r _remove_r _vfprintf_r
_iprintf_r _rename_r _vsnprintf_r
_mkstemp_r _snprintf_r _vsprintf_r
_mktemp_t _sprintf_r
_Signal functions:_
_init_signal_r _signal_r
_kill_r __sigtramp_r
_raise_r
_Stdlib functions:_
_calloc_r _mblen_r _setenv_r
_dtoa_r _mbstowcs_r _srand_r
_free_r _mbtowc_r _strtod_r
_getenv_r _memalign_r _strtol_r
_mallinfo_r _mstats_r _strtoul_r
_malloc_r _putenv_r _system_r
_malloc_r _rand_r _wcstombs_r
_malloc_stats_r _realloc_r _wctomb_r
_String functions:_
_strdup_r _strtok_r
_System functions:_
_close_r _link_r _unlink_r
_execve_r _lseek_r _wait_r
_fcntl_r _open_r _write_r
_fork_r _read_r
_fstat_r _sbrk_r
_gettimeofday_r _stat_r
_getpid_r _times_r
_Time function:_
_asctime_r

File: libc.info, Node: Misc, Next: Xtensa, Prev: Reentrancy, Up: Top
11 Miscellaneous Macros and Functions
*************************************
This chapter describes miscellaneous routines not covered elsewhere.
* Menu:
* ffs:: Return first bit set in a word
* unctrl:: Return printable representation of a character

File: libc.info, Node: ffs, Next: unctrl, Up: Misc
11.1 `ffs'--find first bit set in a word
========================================
*Synopsis*
#include <strings.h>
int ffs(int WORD);
*Description*
`ffs' returns the first bit set in a word.
*Returns*
`ffs' returns 0 if C is 0, 1 if C is odd, 2 if C is a multiple of 2,
etc.
*Portability*
`ffs' is not ANSI C.
No supporting OS subroutines are required.

File: libc.info, Node: unctrl, Prev: ffs, Up: Misc
11.2 `unctrl'--get printable representation of a character
==========================================================
*Synopsis*
#include <unctrl.h>
char *unctrl(int C);
int unctrllen(int C);
*Description*
`unctrl' is a macro which returns the printable representation of C as
a string. `unctrllen' is a macro which returns the length of the
printable representation of C.
*Returns*
`unctrl' returns a string of the printable representation of C.
`unctrllen' returns the length of the string which is the printable
representation of C.
*Portability*
`unctrl' and `unctrllen' are not ANSI C.
No supporting OS subroutines are required.

File: libc.info, Node: Xtensa, Next: Syscalls, Prev: Misc, Up: Top
12 Functions for Xtensa Processors
**********************************
This chapter describes machine-dependent functions that are included in
the C library when it is built for Xtensa processors.
* Menu:
* setjmp:: Save stack environment
* longjmp:: Non-local goto

File: libc.info, Node: setjmp, Next: longjmp, Up: Xtensa
12.1 `setjmp'--save stack environment
=====================================
*Synopsis*
#include <setjmp.h>
int setjmp(jmp_buf env);
*Description*
`setjmp' and `longjmp' are useful for dealing with errors and
interrupts encountered in a low-level subroutine of a program.
`setjmp' saves the stack context/environment in `env' for later use by
`longjmp'. The stack context will be invalidated if the function which
called `setjmp' returns.
*Returns*
`setjmp' returns 0 if returning directly, and non-zero when returning
from `longjmp' using the saved context.
*Portability*
`setjmp' is ANSI C and POSIX.1.
setjmp requires no supporting OS subroutines.

File: libc.info, Node: longjmp, Prev: setjmp, Up: Xtensa
12.2 `longjmp'--non-local goto
==============================
*Synopsis*
#include <setjmp.h>
void longjmp(jmp_buf env, int val);
*Description*
`longjmp' and `setjmp' are useful for dealing with errors and
interrupts encountered in a low-level subroutine of a program.
`longjmp' restores the environment saved by the last call of `setjmp'
with the corresponding `env' argument. After `longjmp' is completed,
program execution continues as if the corresponding call of `setjmp'
had just returned the value `val'. `longjmp' cannot cause 0 to be
returned. If `longjmp' is invoked with a second argument of 0, 1 will
be returned instead.
*Returns*
This function never returns.
*Portability*
`longjmp' is ANSI C and POSIX.1.
longjmp requires no supporting OS subroutines.

File: libc.info, Node: Syscalls, Next: Arglists, Prev: Xtensa, Up: Top
13 System Calls
***************
The C subroutine library depends on a handful of subroutine calls for
operating system services. If you use the C library on a system that
complies with the POSIX.1 standard (also known as IEEE 1003.1), most of
these subroutines are supplied with your operating system.
If some of these subroutines are not provided with your system--in
the extreme case, if you are developing software for a "bare board"
system, without an OS--you will at least need to provide do-nothing
stubs (or subroutines with minimal functionality) to allow your
programs to link with the subroutines in `libc.a'.
System routines may be provided in either reentrant or non-reentrant
versions. The reentrant versions take an extra argument for the
reentrancy structure and have different names, formed by prepending `_'
and appending `_r' (e.g., `_close_r' instead of `close'). If newlib is
configured to use reentrant system routines, the non-reentrant versions
of the system routines are provided as cover routines. Likewise, if
newlib is configured to use non-reentrant system routines, reentrant
cover routines are provided that achieve reentrancy by using a reserved
global data block. *Note Reentrancy: Reentrancy.
* Menu:
* Stubs:: Definitions for OS interface
* Xtensa Syscalls:: System calls in the default Xtensa runtime

File: libc.info, Node: Stubs, Next: Xtensa Syscalls, Up: Syscalls
13.1 Definitions for OS interface
=================================
This is the complete set of system definitions (primarily subroutines)
required; the examples shown implement the minimal functionality
required to allow `libc' to link, and fail gracefully where OS services
are not available.
Graceful failure is permitted by returning an error code. If newlib
is configured to use non-reentrant system routines, a minor
complication arises here: the C library must be compatible with
development environments that supply fully functional versions of these
subroutines. Such environments usually return error codes in a global
`errno'. However, the Red Hat newlib C library provides a _macro_
definition for `errno' in the header file `errno.h', as part of its
support for reentrant routines (*note Reentrancy: Reentrancy.).
The bridge between these two interpretations of `errno' is
straightforward: the C library routines with OS interface calls capture
the `errno' values returned globally, and record them in the
appropriate field of the reentrancy structure (so that you can query
them using the `errno' macro from `errno.h').
This mechanism becomes visible when you write non-reentrant stub
routines for OS interfaces. You must include `errno.h', then disable
the macro, like this:
#include <errno.h>
#undef errno
extern int errno;
The examples in this chapter include this treatment of `errno'. If you
are writing reentrant stub routines, this issue is irrelevant because
the error code is stored into the reentrancy structure and there is no
need for a global variable.
For simplicity, only the non-reentrant versions of the system
routines are shown here. The reentrant versions are similar except for
the function names, the extra reentrancy structure argument, and the
error codes being stored into the reentrancy structure instead of the
global `errno' variable.
`_exit'
Exit a program without cleaning up files. If your system doesn't
provide this, it is best to avoid linking with subroutines that
require it (`exit', `system'). Note that there is no separate
reentrant version of this routine, even when newlib is configured
to use reentrant system routines.
`close'
Close a file. Minimal implementation:
int close(int file) {
return -1;
}
`environ'
A pointer to a list of environment variables and their values.
For a minimal environment, this empty list is adequate:
char *__env[1] = { 0 };
char **environ = __env;
`execve'
Transfer control to a new process. Minimal implementation (for a
system without processes):
#include <errno.h>
#undef errno
extern int errno;
int execve(char *name, char **argv, char **env) {
errno = ENOMEM;
return -1;
}
`fcntl'
File control commands. Minimal implementation:
int fcntl(int fildes, int cmd, int arg) {
errno = EAGAIN;
return -1;
}
`fork'
Create a new process. Minimal implementation (for a system
without processes):
#include <errno.h>
#undef errno
extern int errno;
int fork(void) {
errno = EAGAIN;
return -1;
}
`fstat'
Status of an open file. For consistency with other minimal
implementations in these examples, all files are regarded as
character special devices. The `sys/stat.h' header file required
is distributed in the `include' subdirectory for this C library.
#include <sys/stat.h>
int fstat(int file, struct stat *st) {
st->st_mode = S_IFCHR;
return 0;
}
`getpid'
Process-ID; this is sometimes used to generate strings unlikely to
conflict with other processes. Minimal implementation, for a
system without processes:
int getpid(void) {
return 1;
}
`gettimeofday'
Get the current time. Minimal implementation:
#include <sys/time.h>
int gettimeofday(struct timeval *tv,
struct timezone *tz) {
errno = EINVAL;
return -1;
}
`kill'
Send a signal. Minimal implementation:
#include <errno.h>
#undef errno
extern int errno;
int kill(int pid, int sig) {
errno = EINVAL;
return -1;
}
`link'
Establish a new name for an existing file. Minimal implementation:
#include <errno.h>
#undef errno
extern int errno;
int link(char *old, char *new) {
errno = EMLINK;
return -1;
}
`lseek'
Set position in a file. Minimal implementation:
int lseek(int file, int ptr, int dir) {
return 0;
}
`open'
Open a file. Minimal implementation:
int open(const char *name, int flags, int mode) {
return -1;
}
`read'
Read from a file. Minimal implementation:
int read(int file, char *ptr, int len) {
return 0;
}
`_rename'
Rename a file. For systems that do not support the `link' system
routine, newlib can be configured to use this optional routine for
renaming files. Note that the reentrant version of this routine is
named `_rename_r'. Minimal implementation:
int _rename(char *oldpath, char *newpath) {
errno = EINVAL;
return -1;
}
`sbrk'
Increase program data space. As `malloc' and related functions
depend on this, it is useful to have a working implementation. The
following suffices for a standalone system; it exploits the symbol
`_end' automatically defined by the GNU linker.
caddr_t sbrk(int incr) {
extern char _end; /* Defined by the linker */
static char *heap_end;
char *prev_heap_end;
if (heap_end == 0) {
heap_end = &_end;
}
prev_heap_end = heap_end;
if (heap_end + incr > stack_ptr) {
write (1, "Heap and stack collision\n", 25);
abort ();
}
heap_end += incr;
return (caddr_t) prev_heap_end;
}
`stat'
Status of a file (by name). Minimal implementation:
int stat(char *file, struct stat *st) {
st->st_mode = S_IFCHR;
return 0;
}
`times'
Timing information for current process. Minimal implementation:
int times(struct tms *buf) {
return -1;
}
`unlink'
Remove a file's directory entry. Minimal implementation:
#include <errno.h>
#undef errno
extern int errno;
int unlink(char *name) {
errno = ENOENT;
return -1;
}
`wait'
Wait for a child process. Minimal implementation:
#include <errno.h>
#undef errno
extern int errno;
int wait(int *status) {
errno = ECHILD;
return -1;
}
`write'
Write to a file. `libc' subroutines will use this system routine
for output to all files, _including_ `stdout'--so if you need to
generate any output, for example to a serial port for debugging,
you should make your minimal `write' capable of doing this. The
following minimal implementation is an incomplete example; it
relies on an `outbyte' subroutine (not shown; typically, you must
write this in assembler from examples provided by your hardware
manufacturer) to actually perform the output.
int write(int file, char *ptr, int len) {
int todo;
for (todo = 0; todo < len; todo++) {
outbyte (*ptr++);
}
return len;
}

File: libc.info, Node: Xtensa Syscalls, Prev: Stubs, Up: Syscalls
13.2 Xtensa system calls
========================
If you are not using an operating system, the default Xtensa runtime
environment provides three options for system calls. The first option
is the GNU low-level operating system support library (libgloss), which
provides minimal stub routines, similar to those described above (*note
Stubs::). Please refer to the `Xtensa Linker Support Packages (LSPs)
Reference Manual' for instructions on modifying and rebuilding libgloss.
The second and third options both pass some system calls to a host
machine, where they are evaluated before passing the results back to
the target system. With this approach, your Xtensa system can access
the file system of the host machine, which is often useful for
development and debugging. The "sim" library uses the "semihosting"
feature of the Xtensa instruction set simulator (ISS) to implement
system calls that pass through to the host running the ISS. This is
the default when running on the Xtensa ISS. The "gdbio" library uses
the "File-I/O" remote protocol extension of the GNU debugger (GDB) to
pass system calls via the On-Chip Debugging (OCD) interface to a host
machine running GDB. See the `Xtensa Software Development Toolkit
User's Guide' for information about using the gdbio library. The
"File-I/O remote protocol extension" appendix section in the `GNU
Debugger User's Guide' describes the details of this feature.
Tensilica configures newlib to use reentrant system call interfaces.
The actual system call implementations may not all be reentrant; see
the `Xtensa Linker Support Packages (LSPs) Reference Manual' for
details. The system routines are listed in this section with the
reentrant function names.
* Menu:
* Xtensa Libgloss:: The Xtensa version of libgloss.
* Xtensa ISS Syscalls:: System calls supported by the ISS.
* Xtensa gdbio:: System calls supported by gdbio.

File: libc.info, Node: Xtensa Libgloss, Next: Xtensa ISS Syscalls, Up: Xtensa Syscalls
13.2.1 System calls with the libgloss library
---------------------------------------------
The Xtensa libgloss library implements the system routines as described
below. Some of the routines are not implemented; programs using
libgloss must avoid linking with functions that require those
unimplemented routines.
`_exit'
Not implemented. It is assumed that this function is provided
elsewhere, typically in the `crt1' file.
`_close_r'
Does nothing. Returns 0.
`environ'
Not implemented. The default implementation in newlib is used
unless another definition is provided elsewhere.
`_execve_r'
Not implemented.
`_fcntl_r'
Not implemented.
`_fork_r'
Not implemented.
`_fstat_r'
Assumes terminal I/O and sets `st_mode' to `S_IFCHR'. Returns 0.
`_getpid_r'
Returns 1.
`_gettimeofday_r'
Not implemented.
`_kill_r'
Calls `_exit' if the specified process ID is 1 (as returned by
`getpid'); otherwise, does nothing. Returns 0.
`_link_r'
Not implemented.
`_lseek_r'
Sets `errno' to `ESPIPE'. Returns -1.
`_open_r'
Sets `errno' to `EIO'. Returns -1.
`_read_r'
Reads the specified number of bytes from the serial port using a
board-specific `inbyte' function. Ignores the file descriptor
argument. The `inbyte' function is not part of libgloss and must
be provided elsewhere.
`_rename_r'
Not implemented.
`_sbrk_r'
Grows the heap. If the end of the heap extends beyond the
`_heap_sentry' symbol (set by the linker), sets `errno' to
`ENOMEM' and returns -1. Note that unlike the ISS semihosting
version of `_sbrk_r', this version does not currently check if the
heap collides with the stack.
`_stat_r'
Sets `errno' to `EIO' and returns -1.
`_times_r'
Returns the current cycle count value if the Xtensa processor
configuration includes the Timer Interrupt Option; otherwise, sets
`errno' to `ENOSYS' and returns -1.
`_unlink_r'
Sets `errno' to `EIO'. Returns -1.
`_wait_r'
Not implemented.
`_write_r'
Writes the specified number of bytes to the serial port using the
board-specific `outbyte' function. Ignores the file descriptor
argument. The `outbyte' function is not included in libgloss and
must be provided elsewhere.

File: libc.info, Node: Xtensa ISS Syscalls, Next: Xtensa gdbio, Prev: Xtensa Libgloss, Up: Xtensa Syscalls
13.2.2 System calls with the Xtensa ISS
---------------------------------------
The Xtensa ISS semihosting library provides the following system
routines (all the routines using ISS semihosting set `errno' and the
return value based on the status of the host system call):
`_exit'
Terminates the Xtensa ISS simulation.
`_close_r'
Closes the specified host file using the ISS semihosting interface.
`environ'
Not implemented. It is assumed that this is provided in the
`crt1-sim' file.
`_execve_r'
Not implemented.
`_fcntl_r'
Not implemented.
`_fork_r'
Not implemented.
`_fstat_r'
Assumes terminal I/O and sets `st_mode' to `S_IFCHR'. Returns 0.
`_getpid_r'
Returns 1.
`_gettimeofday_r'
Gets the host system's current time expressed in elapsed seconds
and microseconds since January 1, 1970 using the ISS semihosting
interface.
`_kill_r'
Calls `_exit' if the specified process ID is 1 (as returned by
`getpid'); otherwise, does nothing. Returns 0.
`_link_r'
Adds a hard link to a host file using the ISS semihosting
interface. (Only supported on Unix platforms.)
`_lseek_r'
Seeks to the specified location in a host file using the ISS
semihosting interface.
`_open_r'
Opens the specified file on the host using the ISS semihosting
interface. The following flags are supported: `O_RDONLY',
`O_WRONLY', `O_RDWR', `O_APPEND', `O_CREAT', `O_TRUNC', `O_EXCL',
`O_NDELAY', `O_NONBLOCK', `O_BINARY', and `O_TEXT'.
`_read_r'
Reads from a host file using the ISS semihosting interface.
`_rename_r'
Renames a host file using the ISS semihosting interface.
`_sbrk_r'
Grows the heap. If the end of the heap extends beyond the
`_heap_sentry' symbol (set by the linker) or if it collides with
the stack, sets `errno' to `ENOMEM' and returns -1.
`_stat_r'
Sets `errno' to `EIO' and returns -1.
`_times_r'
Returns the Xtensa simulation cycle count.
`_unlink_r'
Unlinks (i.e., removes) a host file using the ISS semihosting
interface.
`_wait_r'
Not implemented.
`_write_r'
Writes to a host file using the ISS semihosting interface.

File: libc.info, Node: Xtensa gdbio, Prev: Xtensa ISS Syscalls, Up: Xtensa Syscalls
13.2.3 System calls with the gdbio library
------------------------------------------
The Xtensa "gdbio" library (libgdbio) implements the system routines as
described below. Some of the routines are not implemented; programs
using libgdbio must avoid linking with functions that require those
unimplemented routines.
`_exit'
Not implemented. It is assumed that this function is provided
elsewhere, typically in the `crt1' file.
`_close_r'
Closes the specified host file using GDB's File-I/O protocol.
`environ'
Not implemented. The default implementation in newlib is used
unless another definition is provided elsewhere.
`_execve_r'
Not implemented.
`_fcntl_r'
Not implemented.
`_fork_r'
Not implemented.
`_fstat_r'
Gets the status of an open file using GDB's File-I/O protocol.
`_getpid_r'
Returns 1.
`_gettimeofday_r'
Gets the host system's current time expressed in elapsed seconds
and microseconds since January 1, 1970 using GDB's File-I/O
protocol.
`_kill_r'
Calls _exit if the specified process ID is 1 (as returned by
_getpid_r); otherwise, does nothing. Returns 0.
`_link_r'
Not implemented.
`_lseek_r'
Seeks to the specified location in a host file using GDB's
File-I/O protocol.
`_open_r'
Opens the specified file on the host using GDB's File-I/O
protocol. The following flags are supported: `O_RDONLY',
`O_WRONLY', `O_RDWR', `O_APPEND', `O_CREAT', `O_TRUNC', and
`O_EXCL'.
`_read_r'
Reads from a host file using GDB's File-I/O protocol.
`_rename_r'
Renames a host file using GDB's File-I/O protocol.
`_sbrk_r'
Grows the heap. If the end of the heap extends beyond the
_heap_sentry symbol (set by the linker), sets errno to ENOMEM and
returns -1. Note that unlike the ISS semihosting version of
_sbrk_r, this version does not currently check if the heap
collides with the stack.
`_stat_r'
Gets the status of the specified host file using GDB's File-I/O
protocol.
`_times_r'
Returns the current cycle count value if the Xtensa processor
configuration includes the Timer Interrupt Option; otherwise, sets
`errno' to `ENOSYS' and returns -1.
`_unlink_r'
Unlinks (i.e., removes) a host file using GDB's File-I/O protocol.
`_wait_r'
Not implemented.
`_write_r'
Writes to a host file using GDB's File-I/O protocol.
`gdbio_system'
This function provides access to the GDB File-I/O protocol's
`system' function. It is renamed to avoid conflicting with
newlib's standard `system' function. It is only supported on Unix
platforms.
int gdbio_system(const char *command);
The specified command is executed on the host by running "`/bin/sh
-c COMMAND'". The return value is -1 on error, or the exit status
of the command otherwise. Note that this feature is disabled by
default in GDB and must be enabled by changing the "remote
system-call-allowed" setting to a nonzero value.

File: libc.info, Node: Arglists, Next: Library Index, Prev: Syscalls, Up: Top
14 Variable Argument Lists
**************************
The `printf' family of functions is defined to accept a variable number
of arguments, rather than a fixed argument list. You can define your
own functions with a variable argument list, by using macro definitions
from either `stdarg.h' (for compatibility with ANSI C) or from
`varargs.h' (for compatibility with a popular convention prior to ANSI
C).
* Menu:
* Stdarg::
* Varargs::

File: libc.info, Node: Stdarg, Next: Varargs, Up: Arglists
14.1 ANSI-standard macros, `stdarg.h'
=====================================
In ANSI C, a function has a variable number of arguments when its
parameter list ends in an ellipsis (`...'). The parameter list must
also include at least one explicitly named argument; that argument is
used to initialize the variable list data structure.
ANSI C defines three macros (`va_start', `va_arg', and `va_end') to
operate on variable argument lists. `stdarg.h' also defines a special
type to represent variable argument lists: this type is called
`va_list'.
* Menu:
* va_start::
* va_arg::
* va_end::

File: libc.info, Node: va_start, Next: va_arg, Up: Stdarg
14.1.1 Initialize variable argument list
----------------------------------------
*Synopsis*
#include <stdarg.h>
void va_start(va_list AP, RIGHTMOST);
*Description*
Use `va_start' to initialize the variable argument list AP, so that
`va_arg' can extract values from it. RIGHTMOST is the name of the last
explicit argument in the parameter list (the argument immediately
preceding the ellipsis `...' that flags variable arguments in an ANSI C
function header). You can only use `va_start' in a function declared
using this ellipsis notation (not, for example, in one of its
subfunctions).
*Returns*
`va_start' does not return a result.
*Portability*
ANSI C requires `va_start'.

File: libc.info, Node: va_arg, Next: va_end, Prev: va_start, Up: Stdarg
14.1.2 Extract a value from argument list
-----------------------------------------
*Synopsis*
#include <stdarg.h>
TYPE va_arg(va_list AP, TYPE);
*Description*
`va_arg' returns the next unprocessed value from a variable argument
list AP (which you must previously create with VA_START). Specify the
type for the value as the second parameter to the macro, TYPE.
You may pass a `va_list' object AP to a subfunction, and use
`va_arg' from the subfunction rather than from the function actually
declared with an ellipsis in the header; however, in that case you may
_only_ use `va_arg' from the subfunction. ANSI C does not permit
extracting successive values from a single variable-argument list from
different levels of the calling stack.
There is no mechanism for testing whether there is actually a next
argument available; you might instead pass an argument count (or some
other data that implies an argument count) as one of the fixed arguments
in your function call.
*Returns*
`va_arg' returns the next argument, an object of type TYPE.
*Portability*
ANSI C requires `va_arg'.

File: libc.info, Node: va_end, Prev: va_arg, Up: Stdarg
14.1.3 Abandon a variable argument list
---------------------------------------
*Synopsis*
#include <stdarg.h>
void va_end(va_list AP);
*Description*
Use `va_end' to declare that your program will not use the variable
argument list AP any further.
*Returns*
`va_end' does not return a result.
*Portability*
ANSI C requires `va_end'.

File: libc.info, Node: Varargs, Prev: Stdarg, Up: Arglists
14.2 Traditional macros, `varargs.h'
====================================
If your C compiler predates ANSI C, you may still be able to use
variable argument lists using the macros from the `varargs.h' header
file. These macros resemble their ANSI counterparts, but have
important differences in usage. In particular, since traditional C has
no declaration mechanism for variable argument lists, two additional
macros are provided simply for the purpose of defining functions with
variable argument lists.
As with `stdarg.h', the type `va_list' is used to hold a data
structure representing a variable argument list.
* Menu:
* va_alist::
* va_start-trad::
* va_arg-trad::
* va_end-trad::

File: libc.info, Node: va_alist, Next: va_start-trad, Up: Varargs
14.2.1 Declare variable arguments
---------------------------------
*Synopsis*
#include <varargs.h>
FUNCTION(va_alist)
va_dcl
*Description*
To use the `varargs.h' version of variable argument lists, you must
declare your function with a call to the macro `va_alist' as its
argument list, and use `va_dcl' as the declaration. _Do not use a
semicolon after `va_dcl'._
*Returns*
These macros cannot be used in a context where a return is syntactically
possible.
*Portability*
VA_ALIST and VA_DCL were the most widespread method of declaring
variable argument lists prior to ANSI C.

File: libc.info, Node: va_start-trad, Next: va_arg-trad, Prev: va_alist, Up: Varargs
14.2.2 Initialize variable argument list
----------------------------------------
*Synopsis*
#include <varargs.h>
va_list AP;
va_start(AP);
*Description*
With the `varargs.h' macros, use `va_start' to initialize a data
structure AP to permit manipulating a variable argument list. AP must
have the type VA_ALIST.
*Returns*
`va_start' does not return a result.
*Portability*
`va_start' is also defined as a macro in ANSI C, but the definitions
are incompatible; the ANSI version has another parameter besides AP.

File: libc.info, Node: va_arg-trad, Next: va_end-trad, Prev: va_start-trad, Up: Varargs
14.2.3 Extract a value from argument list
-----------------------------------------
*Synopsis*
#include <varargs.h>
TYPE va_arg(va_list AP, TYPE);
*Description*
`va_arg' returns the next unprocessed value from a variable argument
list AP (which you must previously create with VA_START). Specify the
type for the value as the second parameter to the macro, TYPE.
*Returns*
`va_arg' returns the next argument, an object of type TYPE.
*Portability*
The `va_arg' defined in `varargs.h' has the same syntax and usage as
the ANSI C version from `stdarg.h'.

File: libc.info, Node: va_end-trad, Prev: va_arg-trad, Up: Varargs
14.2.4 Abandon a variable argument list
---------------------------------------
*Synopsis*
#include <varargs.h>
va_end(va_list AP);
*Description*
Use `va_end' to declare that your program will not use the variable
argument list AP any further.
*Returns*
`va_end' does not return a result.
*Portability*
The `va_end' defined in `varargs.h' has the same syntax and usage as
the ANSI C version from `stdarg.h'.

File: libc.info, Node: Library Index, Prev: Arglists, Up: Top
Index
*****
[index]
* Menu:
* __env_lock: __env_lock. (line 6)
* __env_unlock: __env_lock. (line 6)
* __fpurge: fpurge. (line 6)
* __malloc_lock: __malloc_lock. (line 6)
* __malloc_unlock: __malloc_lock. (line 6)
* __tz_lock: __tz_lock. (line 6)
* __tz_unlock: __tz_lock. (line 6)
* _asctime_r: asctime. (line 6)
* _asiprintf_r: siprintf. (line 6)
* _asniprintf_r: siprintf. (line 6)
* _asnprintf_r: sprintf. (line 6)
* _asprintf_r: sprintf. (line 6)
* _atoi_r: atoi. (line 6)
* _atol_r: atoi. (line 6)
* _atoll_r: atoll. (line 6)
* _calloc_r: calloc. (line 6)
* _diprintf_r: diprintf. (line 6)
* _dprintf_r: dprintf. (line 6)
* _exit: Stubs. (line 45)
* _Exit: _Exit. (line 6)
* _fclose_r: fclose. (line 6)
* _fcloseall_r: fcloseall. (line 6)
* _fdopen_r: fdopen. (line 6)
* _fflush_r: fflush. (line 6)
* _fgetc_r: fgetc. (line 6)
* _fgetpos_r: fgetpos. (line 6)
* _fgets_r: fgets. (line 6)
* _fgetwc_r: fgetwc. (line 6)
* _fgetws_r: fgetws. (line 6)
* _fiprintf_r: siprintf. (line 6)
* _fiscanf_r: siscanf. (line 6)
* _fopen_r: fopen. (line 6)
* _fprintf_r: sprintf. (line 6)
* _fpurge_r: fpurge. (line 6)
* _fputc_r: fputc. (line 6)
* _fputs_r: fputs. (line 6)
* _fputwc_r: fputwc. (line 6)
* _fputws_r: fputws. (line 6)
* _fread_r: fread. (line 6)
* _free_r: malloc. (line 6)
* _freopen_r: freopen. (line 6)
* _fscanf_r: sscanf. (line 6)
* _fseek_r: fseek. (line 6)
* _fseeko_r: fseek. (line 6)
* _fsetpos_r: fsetpos. (line 6)
* _ftell_r: ftell. (line 6)
* _ftello_r: ftell. (line 6)
* _fwide_r: fwide. (line 6)
* _fwprintf_r: swprintf. (line 6)
* _fwrite_r: fwrite. (line 6)
* _fwscanf_r: swscanf. (line 6)
* _getc_r: getc. (line 6)
* _getc_unlocked_r: getc_unlocked. (line 6)
* _getchar_r: getchar. (line 6)
* _getchar_unlocked_r: getchar_unlocked. (line 6)
* _gets_r: gets. (line 6)
* _getwc_r: fgetwc. (line 6)
* _getwchar_r: getwchar. (line 6)
* _impure_ptr: Reentrancy. (line 48)
* _iprintf_r: siprintf. (line 6)
* _iscanf_r: siscanf. (line 6)
* _localeconv_r: setlocale. (line 6)
* _mallinfo_r: mallinfo. (line 6)
* _malloc_r: malloc. (line 6)
* _malloc_stats_r: mallinfo. (line 6)
* _malloc_usable_size_r: malloc. (line 6)
* _mallopt_r: mallinfo. (line 6)
* _mbsnrtowcs_r: mbsrtowcs. (line 6)
* _mbsrtowcs_r: mbsrtowcs. (line 6)
* _memalign_r: malloc. (line 6)
* _mkdtemp_r: mktemp. (line 6)
* _mkostemp_r: mktemp. (line 6)
* _mkostemps_r: mktemp. (line 6)
* _mkstemp_r: mktemp. (line 6)
* _mkstemps_r: mktemp. (line 6)
* _mktemp_r: mktemp. (line 6)
* _perror_r: perror. (line 6)
* _printf_r: sprintf. (line 6)
* _putc_r: putc. (line 6)
* _putc_unlocked_r: putc_unlocked. (line 6)
* _putchar_r: putchar. (line 6)
* _puts_r: puts. (line 6)
* _putwc_r: fputwc. (line 6)
* _putwchar_r: putwchar. (line 6)
* _raise_r: raise. (line 6)
* _realloc_r: malloc. (line 6)
* _reallocf_r: malloc. (line 6)
* _reent: Reentrancy. (line 31)
* _remove_r: remove. (line 6)
* _rename: Stubs. (line 172)
* _rewind_r: rewind. (line 6)
* _scanf_r: sscanf. (line 6)
* _setlocale_r: setlocale. (line 6)
* _signal_r: signal. (line 6)
* _siprintf_r: siprintf. (line 6)
* _siscanf_r: siscanf. (line 6)
* _sniprintf_r: siprintf. (line 6)
* _snprintf_r: sprintf. (line 6)
* _sprintf_r: sprintf. (line 6)
* _sscanf_r: sscanf. (line 6)
* _strtod_r: strtod. (line 6)
* _strtol_r: strtol. (line 6)
* _strtoll_r: strtoll. (line 6)
* _strtoul_r: strtoul. (line 6)
* _strtoull_r: strtoull. (line 6)
* _swprintf_r: swprintf. (line 6)
* _swscanf_r: swscanf. (line 6)
* _system_r: system. (line 6)
* _tempnam_r: tmpnam. (line 6)
* _tmpfile_r: tmpfile. (line 6)
* _tmpnam_r: tmpnam. (line 6)
* _tolower: tolower. (line 6)
* _toupper: toupper. (line 6)
* _tzset_r: tzset. (line 6)
* _ungetc_r: ungetc. (line 6)
* _ungetwc_r: ungetwc. (line 6)
* _vasiprintf_r: viprintf. (line 6)
* _vasniprintf_r: viprintf. (line 6)
* _vasnprintf_r: vfprintf. (line 6)
* _vasprintf_r: vfprintf. (line 6)
* _vdiprintf_r: diprintf. (line 6)
* _vdprintf_r: dprintf. (line 6)
* _vfiprintf_r: viprintf. (line 6)
* _vfiscanf_r: viscanf. (line 6)
* _vfprintf_r: vfprintf. (line 6)
* _vfscanf_r: vfscanf. (line 6)
* _vfwprintf_r: vfwprintf. (line 6)
* _vfwscanf: vfwscanf. (line 6)
* _viprintf_r: viprintf. (line 6)
* _viscanf_r: viscanf. (line 6)
* _vprintf_r: vfprintf. (line 6)
* _vscanf_r: vfscanf. (line 6)
* _vsiprintf_r: viprintf. (line 6)
* _vsiscanf_r: viscanf. (line 6)
* _vsniprintf_r: viprintf. (line 6)
* _vsnprintf_r: vfprintf. (line 6)
* _vsprintf_r: vfprintf. (line 6)
* _vsscanf_r: vfscanf. (line 6)
* _vswprintf_r: vfwprintf. (line 6)
* _vswscanf: vfwscanf. (line 6)
* _vwprintf_r: vfwprintf. (line 6)
* _vwscanf: vfwscanf. (line 6)
* _wcsdup_r: wcsdup. (line 6)
* _wcsnrtombs_r: wcsrtombs. (line 6)
* _wcsrtombs_r: wcsrtombs. (line 6)
* _wcstod_r: wcstod. (line 6)
* _wcstof_r: wcstod. (line 6)
* _wcstol_r: wcstol. (line 6)
* _wcstoll_r: wcstoll. (line 6)
* _wcstoul_r: wcstoul. (line 6)
* _wcstoull_r: wcstoull. (line 6)
* _wprintf_r: swprintf. (line 6)
* _wscanf_r: swscanf. (line 6)
* a64l: a64l. (line 6)
* abort: abort. (line 6)
* abs: abs. (line 6)
* asctime: asctime. (line 6)
* asiprintf: siprintf. (line 6)
* asniprintf: siprintf. (line 6)
* asnprintf: sprintf. (line 6)
* asprintf: sprintf. (line 6)
* assert: assert. (line 6)
* atexit: atexit. (line 6)
* atof: atof. (line 6)
* atoff: atof. (line 6)
* atoi: atoi. (line 6)
* atol: atoi. (line 6)
* atoll: atoll. (line 6)
* bcmp: bcmp. (line 6)
* bsearch: bsearch. (line 6)
* bzero: bzero. (line 6)
* calloc: calloc. (line 6)
* clearerr: clearerr. (line 6)
* clock: clock. (line 6)
* close: Stubs. (line 52)
* ctime: ctime. (line 6)
* ctime_r: ctime. (line 6)
* difftime: difftime. (line 6)
* diprintf: diprintf. (line 6)
* div: div. (line 6)
* dprintf: dprintf. (line 6)
* drand48: rand48. (line 6)
* ecvt: ecvt. (line 6)
* ecvtbuf: ecvtbuf. (line 6)
* ecvtf: ecvt. (line 6)
* environ <1>: Stubs. (line 59)
* environ: getenv. (line 6)
* erand48: rand48. (line 6)
* errno global vs macro: Stubs. (line 20)
* execve: Stubs. (line 66)
* exit: exit. (line 6)
* extra argument, reentrant fns: Reentrancy. (line 55)
* fclose: fclose. (line 6)
* fcloseall: fcloseall. (line 6)
* fcntl: Stubs. (line 78)
* fcvt: ecvt. (line 6)
* fcvtbuf: ecvtbuf. (line 6)
* fcvtf: ecvt. (line 6)
* fdopen: fdopen. (line 6)
* feof: feof. (line 6)
* ferror: ferror. (line 6)
* fflush: fflush. (line 6)
* ffs: ffs. (line 6)
* fgetc: fgetc. (line 6)
* fgetpos: fgetpos. (line 6)
* fgets: fgets. (line 6)
* fgetwc: fgetwc. (line 6)
* fgetws: fgetws. (line 6)
* fileno: fileno. (line 6)
* fiprintf: siprintf. (line 6)
* fiscanf: siscanf. (line 6)
* fmemopen: fmemopen. (line 6)
* fopen: fopen. (line 6)
* fopencookie: fopencookie. (line 6)
* fork: Stubs. (line 86)
* fprintf: sprintf. (line 6)
* fpurge: fpurge. (line 6)
* fputc: fputc. (line 6)
* fputs: fputs. (line 6)
* fputwc: fputwc. (line 6)
* fputws: fputws. (line 6)
* fread: fread. (line 6)
* free: malloc. (line 6)
* freopen: freopen. (line 6)
* fropen: funopen. (line 6)
* fscanf: sscanf. (line 6)
* fseek: fseek. (line 6)
* fseeko: fseek. (line 6)
* fsetpos: fsetpos. (line 6)
* fstat: Stubs. (line 98)
* ftell: ftell. (line 6)
* ftello: ftell. (line 6)
* funopen: funopen. (line 6)
* fwide: fwide. (line 6)
* fwopen: funopen. (line 6)
* fwprintf: swprintf. (line 6)
* fwrite: fwrite. (line 6)
* fwscanf: swscanf. (line 6)
* gcvt: gvcvt. (line 6)
* gcvtf: gvcvt. (line 6)
* getc: getc. (line 6)
* getc_unlocked: getc_unlocked. (line 6)
* getchar: getchar. (line 6)
* getchar_unlocked: getchar_unlocked. (line 6)
* getdelim: getdelim. (line 6)
* getenv: getenv. (line 6)
* getline: getline. (line 6)
* getpid: Stubs. (line 110)
* gets: gets. (line 6)
* gettimeofday: Stubs. (line 119)
* getw: getw. (line 6)
* getwc: fgetwc. (line 6)
* getwchar: getwchar. (line 6)
* global reentrancy structure: Reentrancy. (line 48)
* gmtime: gmtime. (line 6)
* gmtime_r: gmtime. (line 6)
* index: index. (line 6)
* iprintf: siprintf. (line 6)
* isalnum: isalnum. (line 6)
* isalpha: isalpha. (line 6)
* isascii: isascii. (line 6)
* iscanf: siscanf. (line 6)
* iscntrl: iscntrl. (line 6)
* isdigit: isdigit. (line 6)
* isgraph: isprint. (line 6)
* islower: islower. (line 6)
* isprint: isprint. (line 6)
* ispunct: ispunct. (line 6)
* isspace: isspace. (line 6)
* isupper: isupper. (line 6)
* iswalnum: iswalnum. (line 6)
* iswalpha: iswalpha. (line 6)
* iswblank: iswblank. (line 6)
* iswcntrl: iswcntrl. (line 6)
* iswctype: iswctype. (line 6)
* iswdigit: iswdigit. (line 6)
* iswgraph: iswgraph. (line 6)
* iswlower: iswlower. (line 6)
* iswprint: iswprint. (line 6)
* iswpunct: iswpunct. (line 6)
* iswspace: iswspace. (line 6)
* iswupper: iswupper. (line 6)
* iswxdigit: iswxdigit. (line 6)
* isxdigit: isxdigit. (line 6)
* jrand48: rand48. (line 6)
* kill: Stubs. (line 129)
* l64a: a64l. (line 6)
* labs: labs. (line 6)
* lcong48: rand48. (line 6)
* ldiv: ldiv. (line 6)
* link: Stubs. (line 140)
* linking the C library: Syscalls. (line 6)
* list of reentrant functions: Reentrancy. (line 64)
* llabs: llabs. (line 6)
* lldiv: lldiv. (line 6)
* localeconv: setlocale. (line 6)
* localtime: localtime. (line 6)
* localtime_r: localtime. (line 6)
* longjmp: longjmp. (line 6)
* lrand48: rand48. (line 6)
* lseek: Stubs. (line 151)
* mallinfo: mallinfo. (line 6)
* malloc: malloc. (line 6)
* malloc_stats: mallinfo. (line 6)
* malloc_usable_size: malloc. (line 6)
* mallopt: mallinfo. (line 6)
* mblen: mblen. (line 6)
* mbsnrtowcs: mbsrtowcs. (line 6)
* mbsrtowcs: mbsrtowcs. (line 6)
* mbstowcs: mbstowcs. (line 6)
* mbtowc: mbtowc. (line 6)
* memalign: malloc. (line 6)
* memchr: memchr. (line 6)
* memcmp: memcmp. (line 6)
* memmem: memmem. (line 6)
* memmove: memmove. (line 6)
* memset: memset. (line 6)
* mkdtemp: mktemp. (line 6)
* mkostemp: mktemp. (line 6)
* mkostemps: mktemp. (line 6)
* mkstemp: mktemp. (line 6)
* mkstemps: mktemp. (line 6)
* mktemp: mktemp. (line 6)
* mktime: mktime. (line 6)
* mrand48: rand48. (line 6)
* nrand48: rand48. (line 6)
* on_exit: on_exit. (line 6)
* open: Stubs. (line 158)
* open_memstream: open_memstream. (line 6)
* open_wmemstream: open_memstream. (line 6)
* OS interface subroutines: Stubs. (line 6)
* perror: perror. (line 6)
* printf: sprintf. (line 6)
* psignal: psignal. (line 6)
* putc: putc. (line 6)
* putc_unlocked: putc_unlocked. (line 6)
* putchar: putchar. (line 6)
* putchar_unlocked: putchar_unlocked. (line 6)
* puts: puts. (line 6)
* putw: putw. (line 6)
* putwc: fputwc. (line 6)
* putwchar: putwchar. (line 6)
* qsort: qsort. (line 6)
* raise: raise. (line 6)
* rand: rand. (line 6)
* rand48: rand48. (line 6)
* rand_r: rand. (line 6)
* read: Stubs. (line 165)
* realloc: malloc. (line 6)
* reallocf: malloc. (line 6)
* reent.h: Reentrancy. (line 31)
* reentrancy: Reentrancy. (line 6)
* reentrancy structure: Reentrancy. (line 31)
* reentrant function list: Reentrancy. (line 64)
* remove: remove. (line 6)
* rename: rename. (line 6)
* rewind: rewind. (line 6)
* rindex: rindex. (line 6)
* sbrk: Stubs. (line 183)
* scanf: sscanf. (line 6)
* seed48: rand48. (line 6)
* setbuf: setbuf. (line 6)
* setbuffer: setbuffer. (line 6)
* setjmp: setjmp. (line 6)
* setlinebuf: setlinebuf. (line 6)
* setlocale: setlocale. (line 6)
* setvbuf: setvbuf. (line 6)
* signal: signal. (line 6)
* siprintf: siprintf. (line 6)
* siscanf: siscanf. (line 6)
* sniprintf: siprintf. (line 6)
* snprintf: sprintf. (line 6)
* sprintf: sprintf. (line 6)
* srand: rand. (line 6)
* srand48: rand48. (line 6)
* sscanf: sscanf. (line 6)
* stat: Stubs. (line 207)
* stpcpy: stpcpy. (line 6)
* stpncpy: stpncpy. (line 6)
* strcasecmp: strcasecmp. (line 6)
* strcasestr: strcasestr. (line 6)
* strcat: strcat. (line 6)
* strchr: strchr. (line 6)
* strcmp: strcmp. (line 6)
* strcoll: strcoll. (line 6)
* strcpy: strcpy. (line 6)
* strcspn: strcspn. (line 6)
* strerror: strerror. (line 6)
* strerror_r: strerror_r. (line 6)
* strftime: strftime. (line 6)
* strlen: strlen. (line 6)
* strlwr: strlwr. (line 6)
* strncasecmp: strncasecmp. (line 6)
* strncat: strncat. (line 6)
* strncmp: strncmp. (line 6)
* strncpy: strncpy. (line 6)
* strnlen: strnlen. (line 6)
* strpbrk: strpbrk. (line 6)
* strrchr: strrchr. (line 6)
* strsep: strtok. (line 6)
* strsignal: strsignal. (line 6)
* strspn: strspn. (line 6)
* strstr: strstr. (line 6)
* strtod: strtod. (line 6)
* strtof: strtod. (line 6)
* strtok: strtok. (line 6)
* strtok_r: strtok. (line 6)
* strtol: strtol. (line 6)
* strtoll: strtoll. (line 6)
* strtoul: strtoul. (line 6)
* strtoull: strtoull. (line 6)
* strupr: strupr. (line 6)
* strxfrm: strxfrm. (line 6)
* stubs: Stubs. (line 6)
* subroutines for OS interface: Stubs. (line 6)
* swprintf: swprintf. (line 6)
* swscanf: swscanf. (line 6)
* system: system. (line 6)
* tempnam: tmpnam. (line 6)
* time: time. (line 6)
* times: Stubs. (line 215)
* tmpfile: tmpfile. (line 6)
* tmpnam: tmpnam. (line 6)
* toascii: toascii. (line 6)
* tolower: tolower. (line 6)
* toupper: toupper. (line 6)
* towctrans: towctrans. (line 6)
* towlower: towlower. (line 6)
* towupper: towupper. (line 6)
* tzset: tzset. (line 6)
* unctrl: unctrl. (line 6)
* unctrllen: unctrl. (line 6)
* ungetc: ungetc. (line 6)
* ungetwc: ungetwc. (line 6)
* unlink: Stubs. (line 222)
* va_alist: va_alist. (line 6)
* va_arg <1>: va_arg-trad. (line 6)
* va_arg: va_arg. (line 6)
* va_dcl: va_alist. (line 6)
* va_end <1>: va_end-trad. (line 6)
* va_end: va_end. (line 6)
* va_start <1>: va_start-trad. (line 6)
* va_start: va_start. (line 6)
* vasiprintf: viprintf. (line 6)
* vasniprintf: viprintf. (line 6)
* vasnprintf: vfprintf. (line 6)
* vasprintf: vfprintf. (line 6)
* vdiprintf: diprintf. (line 6)
* vdprintf: dprintf. (line 6)
* vfiprintf: viprintf. (line 6)
* vfiscanf: viscanf. (line 6)
* vfprintf: vfprintf. (line 6)
* vfscanf: vfscanf. (line 6)
* vfwprintf: vfwprintf. (line 6)
* vfwscanf: vfwscanf. (line 6)
* viprintf: viprintf. (line 6)
* viscanf: viscanf. (line 6)
* vprintf: vfprintf. (line 6)
* vscanf: vfscanf. (line 6)
* vsiprintf: viprintf. (line 6)
* vsiscanf: viscanf. (line 6)
* vsniprintf: viprintf. (line 6)
* vsnprintf: vfprintf. (line 6)
* vsprintf: vfprintf. (line 6)
* vsscanf: vfscanf. (line 6)
* vswprintf: vfwprintf. (line 6)
* vswscanf: vfwscanf. (line 6)
* vwprintf: vfwprintf. (line 6)
* vwscanf: vfwscanf. (line 6)
* wait: Stubs. (line 233)
* wcscasecmp: wcscasecmp. (line 6)
* wcscat: wcscat. (line 6)
* wcscoll: wcscoll. (line 6)
* wcsdup: wcsdup. (line 6)
* wcsftime: wcsftime. (line 6)
* wcsncasecmp: wcsncasecmp. (line 6)
* wcsnlen: wcsnlen. (line 6)
* wcsnrtombs: wcsrtombs. (line 6)
* wcsrtombs: wcsrtombs. (line 6)
* wcstod: wcstod. (line 6)
* wcstof: wcstod. (line 6)
* wcstok: wcstok. (line 6)
* wcstol: wcstol. (line 6)
* wcstoll: wcstoll. (line 6)
* wcstombs: wcstombs. (line 6)
* wcstoul: wcstoul. (line 6)
* wcstoull: wcstoull. (line 6)
* wcswidth: wcswidth. (line 6)
* wcsxfrm: wcsxfrm. (line 6)
* wctomb: wctomb. (line 6)
* wctrans: wctrans. (line 6)
* wctype: wctype. (line 6)
* wcwidth: wcwidth. (line 6)
* wprintf: swprintf. (line 6)
* write: Stubs. (line 243)
* wscanf: swscanf. (line 6)
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