NAME
posix_trace_attr_getinherited, posix_trace_attr_getlogfullpolicy,
posix_trace_attr_getstreamfullpolicy, posix_trace_attr_setinherited,
posix_trace_attr_setlogfullpolicy, posix_trace_attr_setstreamfullpolicy
- retrieve and set the behavior of a trace stream (TRACING)
SYNOPSIS
#include <trace.h>
int posix_trace_attr_getinherited(const trace_attr_t *restrict attr,
int *restrict inheritancepolicy);
int posix_trace_attr_getlogfullpolicy(const trace_attr_t *restrict
attr,
int *restrict logpolicy);
int posix_trace_attr_getstreamfullpolicy(const trace_attr_t *attr,
int *streampolicy);
int posix_trace_attr_setinherited(trace_attr_t *attr,
int inheritancepolicy);
int posix_trace_attr_setlogfullpolicy(trace_attr_t *attr,
int logpolicy);
int posix_trace_attr_setstreamfullpolicy(trace_attr_t *attr,
int streampolicy);
DESCRIPTION
The posix_trace_attr_getinherited() and posix_trace_attr_setinherited()
functions, respectively, shall get and set the inheritance policy
stored in the inheritance attribute for traced processes across the
fork() and spawn() operations. The inheritance attribute of the
attributes object pointed to by the attr argument shall be set to one
of the following values defined by manifest constants in the <trace.h>
header:
POSIX_TRACE_CLOSE_FOR_CHILD
After a fork() or spawn() operation, the child shall not be
traced, and tracing of the parent shall continue.
POSIX_TRACE_INHERITED
After a fork() or spawn() operation, if the parent is being
traced, its child shall be concurrently traced using the same
trace stream.
The default value for the inheritance attribute is
POSIX_TRACE_CLOSE_FOR_CHILD.
The posix_trace_attr_getlogfullpolicy() and
posix_trace_attr_setlogfullpolicy() functions, respectively, shall get
and set the trace log full policy stored in the log-full-policy
attribute of the attributes object pointed to by the attr argument.
The log-full-policy attribute shall be set to one of the following
values defined by manifest constants in the <trace.h> header:
POSIX_TRACE_LOOP
The trace log shall loop until the associated trace stream is
stopped. This policy means that when the trace log gets full,
the file system shall reuse the resources allocated to the
oldest trace events that were recorded. In this way, the trace
log will always contain the most recent trace events flushed.
POSIX_TRACE_UNTIL_FULL
The trace stream shall be flushed to the trace log until the
trace log is full. This condition can be deduced from the
posix_log_full_status member status (see the
posix_trace_status_info structure defined in <trace.h>). The
last recorded trace event shall be the POSIX_TRACE_STOP trace
event.
POSIX_TRACE_APPEND
The associated trace stream shall be flushed to the trace log
without log size limitation. If the application specifies
POSIX_TRACE_APPEND, the implementation shall ignore the log-max-
size attribute.
The default value for the log-full-policy attribute is
POSIX_TRACE_LOOP.
The posix_trace_attr_getstreamfullpolicy() and
posix_trace_attr_setstreamfullpolicy() functions, respectively, shall
get and set the trace stream full policy stored in the stream-full-
policy attribute of the attributes object pointed to by the attr
argument.
The stream-full-policy attribute shall be set to one of the following
values defined by manifest constants in the <trace.h> header:
POSIX_TRACE_LOOP
The trace stream shall loop until explicitly stopped by the
posix_trace_stop() function. This policy means that when the
trace stream is full, the trace system shall reuse the resources
allocated to the oldest trace events recorded. In this way, the
trace stream will always contain the most recent trace events
recorded.
POSIX_TRACE_UNTIL_FULL
The trace stream will run until the trace stream resources are
exhausted. Then the trace stream will stop. This condition can
be deduced from posix_stream_status and posix_stream_full_status
(see the posix_trace_status_info structure defined in
<trace.h>). When this trace stream is read, a POSIX_TRACE_STOP
trace event shall be reported after reporting the last recorded
trace event. The trace system shall reuse the resources
allocated to any trace events already reported-see the
posix_trace_getnext_event(), posix_trace_trygetnext_event(), and
posix_trace_timedgetnext_event() functions-or already flushed
for an active trace stream with log if the Trace Log option is
supported; see the posix_trace_flush() function. The trace
system shall restart the trace stream when it is empty and may
restart it sooner. A POSIX_TRACE_START trace event shall be
reported before reporting the next recorded trace event.
POSIX_TRACE_FLUSH
If the Trace Log option is supported, this policy is identical
to the POSIX_TRACE_UNTIL_FULL trace stream full policy except
that the trace stream shall be flushed regularly as if
posix_trace_flush() had been explicitly called. Defining this
policy for an active trace stream without log shall be invalid.
The default value for the stream-full-policy attribute shall be
POSIX_TRACE_LOOP for an active trace stream without log.
If the Trace Log option is supported, the default value for the stream-
full-policy attribute shall be POSIX_TRACE_FLUSH for an active trace
stream with log.
RETURN VALUE
Upon successful completion, these functions shall return a value of
zero. Otherwise, they shall return the corresponding error number.
If successful, the posix_trace_attr_getinherited() function shall store
the inheritance attribute value in the object pointed to by
inheritancepolicy. Otherwise, the content of this object is undefined.
If successful, the posix_trace_attr_getlogfullpolicy() function shall
store the log-full-policy attribute value in the object pointed to by
logpolicy. Otherwise, the content of this object is undefined.
If successful, the posix_trace_attr_getstreamfullpolicy() function
shall store the stream-full-policy attribute value in the object
pointed to by streampolicy. Otherwise, the content of this object is
undefined.
ERRORS
These functions may fail if:
EINVAL The value specified by at least one of the arguments is invalid.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
fork() , posix_trace_attr_init() , posix_trace_create() ,
posix_trace_flush() , posix_trace_get_attr() ,
posix_trace_getnext_event() , posix_trace_start() ,
posix_trace_timedgetnext_event() , 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 .