libtracefs(3)
=============

NAME
----
tracefs_local_events, tracefs_local_events_system, tracefs_fill_local_events -
Initialize a tep handler with trace events from the local system.

SYNOPSIS
--------
[verse]
--
*#include <tracefs.h>*

struct tep_handle pass:[*]*tracefs_local_events*(const char pass:[*]_tracing_dir_);
struct tep_handle pass:[*]*tracefs_local_events_system*(const char pass:[*]_tracing_dir_, const char pass:[*] const pass:[*]_sys_names_);
int *tracefs_fill_local_events*(const char pass:[*]_tracing_dir_, struct tep_handle pass:[*]_tep_, int pass:[*]_parsing_failures_);

--

DESCRIPTION
-----------
Functions for initializing a tep handler with trace events from the local system.

The _tracefs_local_events()_ function allocates a new _tep_ handler and
initializes it with events from all trace systems, located in the given
_tracing_dir_ directory. This could be NULL or the location of the tracefs
mount point for the trace systems of the local machine, or it may be a path
to a copy of the tracefs directory from another machine.

The _tracefs_local_events_system()_ function allocates a new _tep_ handler
and initializes it with events from specified trace systems _sys_names_,
located in the given _tracing_dir_ directory. This could be NULL or the
location of the tracefs mount point for the trace systems of the local
machine, or it may be a path to a copy of the tracefs directory from another
machine. The _sys_names_ argument is an array of trace system names, that
will be used for _tep_ handler initialization. The last element in that
array must be a NULL pointer.

The _tracefs_fill_local_events()_ function initializes already allocated _tep_
handler with events from all trace systems, located in the given _tracing_dir_
directory. This could be NULL or the location of the tracefs mount point
for the trace systems of the local machine, or it may be a path to a copy
of the tracefs directory from another machine. The _tep_ argument must be
a pointer to already allocated tep handler, that is going to be initialized.
The _parsing_failures_ argument could be NULL or a pointer to an integer,
where the number of failures while parsing the event files are returned.

RETURN VALUE
------------
The _tracefs_local_events()_ and _tracefs_local_events_system()_ functions
return pointer to allocated and initialized _tep_ handler, or NULL in
case of an error. The returned _tep_ handler must be freed with _tep_free(3)_.

The _tracefs_fill_local_events()_ function returns -1 in case of an error or
0 otherwise.

EXAMPLE
-------
[source,c]
--
#include <tracefs.h>

struct tep_event *tep;
...
	tep = tracefs_local_events(NULL);
	if (!tep) {
		/* Failed to initialise tep handler with local events from top instance */
		...
	}
...
	tep_free(tep);
...
	const char *systems[] = {"ftrace", "irq", NULL};
	tep = tracefs_local_events_system(NULL, systems);
	if (!tep) {
		/* Failed to initialise tep handler with local events from
		 * ftrace and irq systems in top instance.
		 */
		...
	}
...
	tep_free(tep);
...
	int parsing_failures;
	tep = tep_alloc();
	if (!tep) {
		/* Failed to allocate a tep handler */
		...
	}
	if (tracefs_fill_local_events(NULL, tep, &parsing_failures) < 0) {
		/* Failed to initialise tep handler with local events from top instance */
	}
...
	tep_free(tep);
--
FILES
-----
[verse]
--
*tracefs.h*
	Header file to include in order to have access to the library APIs.
*-ltracefs*
	Linker switch to add when building a program that uses the library.
--

SEE ALSO
--------
_libtracefs(3)_,
_libtraceevent(3)_,
_trace-cmd(1)_

AUTHOR
------
[verse]
--
*Steven Rostedt* <rostedt@goodmis.org>
*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>
--
REPORTING BUGS
--------------
Report bugs to  <linux-trace-devel@vger.kernel.org>

LICENSE
-------
libtracefs is Free Software licensed under the GNU LGPL 2.1

RESOURCES
---------
https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/

COPYING
-------
Copyright \(C) 2020 VMware, Inc. Free use of this software is granted under
the terms of the GNU Public License (GPL).
