POSIX_TRACE_GET_FILTER
Section: POSIX Programmer's Manual (3P)
Updated: 2017
Page Index
PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
posix_trace_get_filter,
posix_trace_set_filter
--- retrieve and set the filter of an initialized trace stream
(
TRACING)
SYNOPSIS
#include <trace.h>
int posix_trace_get_filter(trace_id_t trid, trace_event_set_t *set);
int posix_trace_set_filter(trace_id_t trid,
const trace_event_set_t *set, int how);
DESCRIPTION
The
posix_trace_get_filter()
function shall retrieve, into the argument pointed to by
set,
the actual trace event filter from the trace stream specified by
trid.
The
posix_trace_set_filter()
function shall change the set of filtered trace event types after a
trace stream identified by the
trid
argument is created. This function may be called prior to starting the
trace stream, or while the trace stream is active. By default, if no
call is made to
posix_trace_set_filter(),
all trace events shall be recorded (that is, none of the trace event
types are filtered out).
If this function is called while the trace is in progress, a special
system trace event, POSIX_TRACE_FILTER,
shall be recorded in the trace indicating both the old and the new sets
of filtered trace event types (see
Table 2-4, Trace and Trace Event Filter Options: System Trace Events
and
Table 2-6, Trace, Trace Log, and Trace Event Filter Options: System Trace Events).
If the
posix_trace_set_filter()
function is interrupted by a signal, an error shall be returned and the
filter shall not be changed. In this case, the state of the trace
stream shall not be changed.
The value of the argument
how
indicates the manner in which the set is to be changed and shall have
one of the following values, as defined in the
<trace.h>
header:
- POSIX_TRACE_SET_EVENTSET
-
The resulting set of trace event types to be filtered shall be the
trace event type set pointed to by the argument
set.
- POSIX_TRACE_ADD_EVENTSET
-
The resulting set of trace event types to be filtered shall be the
union of the current set and the trace event type set pointed to by the
argument
set.
- POSIX_TRACE_SUB_EVENTSET
-
The resulting set of trace event types to be filtered shall be all
trace event types in the current set that are not in the set pointed to
by the argument
set;
that is, remove each element of the specified set from the current
filter.
RETURN VALUE
Upon successful completion, these functions shall return a value of
zero. Otherwise, they shall return the corresponding error number.
The
posix_trace_get_filter()
function stores the set of filtered trace event types in
set,
if successful.
ERRORS
These functions shall fail if:
- EINVAL
-
The value of the
trid
argument does not correspond to an active trace stream or the value of
the argument pointed to by
set
is invalid.
- EINTR
-
The operation was interrupted by a signal.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
The
posix_trace_get_filter()
and
posix_trace_set_filter()
functions may be removed in a future version.
SEE ALSO
Table 2-4,
Trace and Trace Event Filter Options: System Trace Events,
Table 2-6,
Trace,
Trace Log,
and Trace Event Filter Options: System Trace Events,
posix_trace_eventset_add()
The Base Definitions volume of POSIX.1-2017,
<trace.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .