libtraceevent(3)

# libtraceevent(3) Manual Page

## NAME

tep_data_type, tep_data_pid,tep_data_preempt_count, tep_data_flags - Extract common fields from a record.

## SYNOPSIS

    #include <event-parse.h>

    enum trace_flag_type {
            TRACE_FLAG_IRQS_OFF,
            TRACE_FLAG_IRQS_NOSUPPORT,
            TRACE_FLAG_NEED_RESCHED,
            TRACE_FLAG_HARDIRQ,
            TRACE_FLAG_SOFTIRQ,
    };

    int tep_data_type(struct tep_handle *tep, struct tep_record *rec);
    int tep_data_pid(struct tep_handle *tep, struct tep_record *rec);
    int tep_data_preempt_count(struct tep_handle *tep, struct tep_record *rec);
    int tep_data_flags(struct tep_handle *tep, struct tep_record *rec);

## DESCRIPTION

This set of functions can be used to extract common fields from a record.

The tep_data_type() function gets the event id from the record rec. It reads the "common_type" field. The tep argument is the trace event parser context.

The tep_data_pid() function gets the process id from the record rec. It reads the "common_pid" field. The tep argument is the trace event parser context.

The tep_data_preempt_count() function gets the preemption count from the record rec. It reads the "common_preempt_count" field. The tep argument is the trace event parser context.

The tep_data_flags() function gets the latency flags from the record rec. It reads the "common_flags" field. The tep argument is the trace event parser context. Supported latency flags are:

            TRACE_FLAG_IRQS_OFF,          Interrupts are disabled.
            TRACE_FLAG_IRQS_NOSUPPORT,    Reading IRQ flag is not supported by the architecture.
            TRACE_FLAG_NEED_RESCHED,      Task needs rescheduling.
            TRACE_FLAG_HARDIRQ,           Hard IRQ is running.
            TRACE_FLAG_SOFTIRQ,           Soft IRQ is running.

## RETURN VALUE

The tep_data_type() function returns an integer, representing the event id.

The tep_data_pid() function returns an integer, representing the process id

The tep_data_preempt_count() function returns an integer, representing the preemption count.

The tep_data_flags() function returns an integer, representing the latency flags. Look at the trace_flag_type enum for supported flags.

All these functions in case of an error return a negative integer.

## EXAMPLE

## 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>, author of libtraceevent.
    Tzvetomir Stoyanov <tz.stoyanov@gmail.com>, author of this man page.

## REPORTING BUGS

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

## LICENSE

libtraceevent is Free Software licensed under the GNU LGPL 2.1

## RESOURCES

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