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