tep_find_common_field(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | FILES | SEE ALSO | AUTHOR | REPORTING BUGS | LICENSE | RESOURCES | NOTES | COLOPHON

LIBTRACEEVENT(3)          libtraceevent Manual          LIBTRACEEVENT(3)

NAME         top

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

SYNOPSIS         top

       #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         top

       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         top

       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         top

           #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         top

           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         top

       libtraceevent(3), trace-cmd(1)

AUTHOR         top

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

REPORTING BUGS         top

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

LICENSE         top

       libtraceevent is Free Software licensed under the GNU LGPL 2.1

RESOURCES         top

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

NOTES         top

        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

COLOPHON         top

       This page is part of the libtraceevent (Linux kernel trace event
       library) project.  Information about the project can be found at
       ⟨https://www.trace-cmd.org/⟩.  If you have a bug report for this
       manual page, see ⟨https://www.trace-cmd.org/⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git⟩
       on 2024-06-14.  (At that time, the date of the most recent commit
       that was found in the repository was 2024-05-17.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

libtraceevent 1.7.3            09/24/2023               LIBTRACEEVENT(3)