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 Trace and Trace Event Filter Options: System Trace 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 <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
None.
SEE ALSO
Trace and Trace Event Filter Options: System Trace Events , Trace,
Trace Log, and Trace Event Filter Options: System Trace Events ,
posix_trace_eventset_add() , the Base Definitions volume of
IEEE Std 1003.1-2001, <trace.h>
COPYRIGHT
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 .