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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | FILES | SEE ALSO | AUTHOR | REPORTING BUGS | LICENSE | RESOURCES | NOTES | COLOPHON |
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LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)
tep_data_type, tep_data_pid, tep_data_preempt_count,
tep_data_flags - Extract common fields from a record.
#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);
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.
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.
#include <event-parse.h>
...
struct tep_handle *tep = tep_alloc();
...
void process_record(struct tep_record *record)
{
int data;
data = tep_data_type(tep, record);
if (data >= 0) {
/* Got the ID of the event */
}
data = tep_data_pid(tep, record);
if (data >= 0) {
/* Got the process ID */
}
data = tep_data_preempt_count(tep, record);
if (data >= 0) {
/* Got the preemption count */
}
data = tep_data_flags(tep, record);
if (data >= 0) {
/* Got the latency flags */
}
}
...
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.
libtraceevent(3), trace-cmd(1)
Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, author of this man page.
Report bugs to <linux-trace-devel@vger.kernel.org[3]>
libtraceevent is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
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
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 2025-08-11. (At that time, the date of the most recent commit
that was found in the repository was 2025-05-30.) 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)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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