libtraceevent(3)
================

NAME
----
tep_find_common_field, tep_find_field, tep_find_any_field -
Search for a field in an event.

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

struct tep_format_field pass:[*]*tep_find_common_field*(struct tep_event pass:[*]_event_, const char pass:[*]_name_);
struct tep_format_field pass:[*]*tep_find_field*(struct tep_event_ormat pass:[*]_event_, const char pass:[*]_name_);
struct tep_format_field pass:[*]*tep_find_any_field*(struct tep_event pass:[*]_event_, const char pass:[*]_name_);
--

DESCRIPTION
-----------
These functions search for a field with given name in an event. The field
returned can be used to find the field content from within a data record.

The _tep_find_common_field()_ function searches for a common field with _name_
in the _event_.

The _tep_find_field()_ function searches for an event specific field with
_name_ in the _event_.

The _tep_find_any_field()_ function searches for any field with _name_ in the
_event_.

RETURN VALUE
------------
The _tep_find_common_field(), _tep_find_field()_ and _tep_find_any_field()_
functions return a pointer to the found field, or NULL in case there is no field
with the requested name.

EXAMPLE
-------
[source,c]
--
#include <event-parse.h>
...
void get_htimer_info(struct tep_handle *tep, struct tep_record *record)
{
	struct tep_format_field *field;
	struct tep_event *event;
	long long softexpires;
	int mode;
	int pid;

	event = tep_find_event_by_name(tep, "timer", "hrtimer_start");

	field = tep_find_common_field(event, "common_pid");
	if (field == NULL) {
		/* Cannot find "common_pid" field in the event */
	} else {
		/* Get pid from the data record */
		pid = tep_read_number(tep, record->data + field->offset,
				      field->size);
	}

	field = tep_find_field(event, "softexpires");
	if (field == NULL) {
		/* Cannot find "softexpires" event specific field in the event */
	} else {
		/* Get softexpires parameter from the data record */
		softexpires = tep_read_number(tep, record->data + field->offset,
					      field->size);
	}

	field = tep_find_any_field(event, "mode");
	if (field == NULL) {
		/* Cannot find "mode" field in the event */
	} else
	{
		/* Get mode parameter from the data record */
		mode = tep_read_number(tep, record->data + field->offset,
				       field->size);
	}
}
...
--

FILES
-----
[verse]
--
*event-parse.h*
	Header file to include in order to have access to the library APIs.
*-ltraceevent*
	Linker switch to add when building a program that uses the library.
--

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

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

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

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