tep_find_common_field - Man Page

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

Referenced By

The man pages tep_find_any_field(3) and tep_find_field(3) are aliases of tep_find_common_field(3).

02/08/2021 libtraceevent 1.1.1 libtraceevent Manual