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LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)

NAME

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

SYNOPSIS

#include <event-parse.h>
struct tep_format_field *tep_find_common_field(struct tep_event *event, const char *name);
struct tep_format_field *tep_find_field(struct tep_event_ormat *event, const char *name);
struct tep_format_field *tep_find_any_field(struct tep_event *event, const char *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

#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

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

Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, author of this man page.

REPORTING BUGS

Report bugs to <linux-trace-devel@vger.kernel.org[3]>

LICENSE

libtraceevent is Free Software licensed under the GNU LGPL 2.1

RESOURCES

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

NOTES

1.
rostedt@goodmis.org
mailto:rostedt@goodmis.org
2.
tz.stoyanov@gmail.com
mailto:tz.stoyanov@gmail.com
3.
linux-trace-devel@vger.kernel.org
mailto:linux-trace-devel@vger.kernel.org
09/24/2022 libtraceevent 1.6.3