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 Trace and
Trace Event Filter Options: SystemTrace Events and 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
The resulting set of trace event types to be filtered shall be the trace
event type set pointed to by the argument set.
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
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.
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.
Trace and Trace Event Filter Options: System Trace Events , Trace,
Trace Log, and Trace Event Filter Options: System TraceEvents ,
posix_trace_eventset_add() , the Base Definitions volume of
IEEE Std 1003.1-2001, <trace.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 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