130 lines
3.4 KiB
Plaintext
130 lines
3.4 KiB
Plaintext
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libtracecmd(3)
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=============
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NAME
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----
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tracecmd_buffer_instances, tracecmd_buffer_instance_name, tracecmd_buffer_instance_handle
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- Read tracing instances from a trace file.
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SYNOPSIS
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--------
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[verse]
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--
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*#include <trace-cmd.h>*
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int *tracecmd_buffer_instances*(struct tracecmd_input pass:[*]_handle_);
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const char pass:[*]*tracecmd_buffer_instance_name*(struct tracecmd_input pass:[*]_handle_, int _indx_);
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struct tracecmd_input pass:[*]*tracecmd_buffer_instance_handle*(struct tracecmd_input pass:[*]_handle_, int _indx_);
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--
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DESCRIPTION
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-----------
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This set of APIs can be used to get information and read tracing data
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from tracing instances stored in a trace file.
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The _tracecmd_buffer_instances()_ function gets the number of tracing
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instances recorded in a trace file. The top instance is not counted.
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The _handle_ is a tracecmd_input handler returned by
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_tracecmd_open_head()_.
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The _tracecmd_buffer_instance_name()_ function gets the name of the
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tracing instance with given index _indx_, recorded in a trace file.
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The _indx_ is a number in the interval [0 .. count-1], where count
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is the number returned by _tracecmd_buffer_instances()_. The _handle_
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is a tracecmd_input handler returned by _tracecmd_open_head()_.
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The _tracecmd_buffer_instance_handle()_ allocates and initializes a
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tracecmd_input handle, associated with trace instance with index
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_indx_ from a trace file. The _handle_ is a tracecmd_input handler
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returned by _tracecmd_open_head()_. The _indx_ is a number in the
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interval [0 .. count-1], where count is the number returned by
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_tracecmd_buffer_instances()_.
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RETURN VALUE
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------------
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The _tracecmd_buffer_instances()_ function returns the number of tracing
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instances recorded in a trace file.
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The _tracecmd_buffer_instance_name()_ function returns a string, the name
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of a tracing instance, or NULL in case of an error The string must *not*
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be freed.
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The _tracecmd_buffer_instance_handle()_ function returns a pointer to
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newly allocated tracecmd_input handler or NULL in case if an error. The
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returned handler must be closed by _tracecmd_close()(3)_
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EXAMPLE
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-------
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[source,c]
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--
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#include <trace-cmd.h>
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...
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struct tracecmd_input *handle = tracecmd_open_head("trace.dat");
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if (!handle) {
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/* Failed to open trace.dat file */
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}
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...
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int num = tracecmd_buffer_instances(handle);
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while(num) {
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struct tracecmd_input *h;
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char *name;
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name = tracecmd_buffer_instance_name(handle, num);
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if (!name) {
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/* Failed to get name of instance num */
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}
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h = tracecmd_buffer_instance_handle(handle, num);
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if (!h) {
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/* Failed to initialize handler for instance num */
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}
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...
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tracecmd_close(h);
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num--;
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}
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...
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tracecmd_close(handle);
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--
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FILES
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-----
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[verse]
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--
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*trace-cmd.h*
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Header file to include in order to have access to the library APIs.
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*-ltracecmd*
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Linker switch to add when building a program that uses the library.
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--
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SEE ALSO
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--------
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_libtracefs(3)_,
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_libtraceevent(3)_,
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_trace-cmd(1)_
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_trace-cmd.dat(5)_
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AUTHOR
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------
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[verse]
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--
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*Steven Rostedt* <rostedt@goodmis.org>
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*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>
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--
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REPORTING BUGS
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--------------
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Report bugs to <linux-trace-devel@vger.kernel.org>
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LICENSE
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-------
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libtracecmd is Free Software licensed under the GNU LGPL 2.1
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RESOURCES
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---------
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https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/
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COPYING
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-------
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Copyright \(C) 2020 VMware, Inc. Free use of this software is granted under
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the terms of the GNU Public License (GPL).
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