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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_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 *restrict
attr, int *restrict 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
The following functions:
posix_trace_attr_getinherited()
posix_trace_attr_getlogfullpolicy()
posix_trace_attr_getstreamfullpolicy()
posix_trace_attr_setinherited()
posix_trace_attr_setlogfullpolicy()
posix_trace_attr_setstreamfullpolicy()
may be removed in a future version.
SEE ALSO
fork(), posix_trace_attr_destroy(), posix_trace_create(), posix_trace_get_attr(),
posix_trace_getnext_event(), posix_trace_start()
The Base Definitions volume of POSIX.1‐2008, <trace.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2013 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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 .