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

libtraceevent                     01/13/2024                  LIBTRACEEVENT(3)