POSIX_TRACE_GET_FILTER(3)  POSIX Programmer's Manual POSIX_TRACE_GET_FILTER(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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 .



IEEE/The Open Group                  2017            POSIX_TRACE_GET_FILTER(3)
