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.TH POSIX_TRACE_EVENTID_EQUAL "3P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"
.SH 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.

.SH NAME
posix_trace_eventid_equal,
posix_trace_eventid_get_name,
posix_trace_trid_eventid_open
\(em manipulate the trace event type identifier
(\fBTRACING\fP)
.SH SYNOPSIS
.LP
.nf
#include <trace.h>
.P
int posix_trace_eventid_equal(trace_id_t \fItrid\fP, trace_event_id_t \fIevent1\fP,
    trace_event_id_t \fIevent2\fP);
int posix_trace_eventid_get_name(trace_id_t \fItrid\fP,
    trace_event_id_t \fIevent\fP, char *\fIevent_name\fP);
int posix_trace_trid_eventid_open(trace_id_t \fItrid\fP,
    const char *restrict \fIevent_name\fP,
    trace_event_id_t *restrict \fIevent\fP);
.fi
.SH DESCRIPTION
The
\fIposix_trace_eventid_equal\fR()
function shall compare the trace event type identifiers
.IR event1
and
.IR event2
from the same trace stream or the same trace log identified by the
.IR trid
argument. If the trace event type identifiers
.IR event1
and
.IR event2
are from different trace streams, the return value shall be
unspecified.
.P
The
\fIposix_trace_eventid_get_name\fR()
function shall return, in the argument pointed to by
.IR event_name ,
the trace event name associated with the trace event type identifier
identified by the argument
.IR event ,
for the trace stream or for the trace log identified by the
.IR trid
argument. The name of the trace event shall have a maximum of
{TRACE_EVENT_NAME_MAX}
characters (which has the minimum value
{_POSIX_TRACE_EVENT_NAME_MAX}).
Successive calls to this function with the same trace event type
identifier and the same trace stream identifier shall return the same
event name.
.P
The
\fIposix_trace_trid_eventid_open\fR()
function shall associate a user trace event name with a trace
event type identifier for a given trace stream. The trace stream is
identified by the
.IR trid
argument, and it shall be an active trace stream. The trace event name
is the string pointed to by the argument
.IR event_name .
It shall have a maximum of
{TRACE_EVENT_NAME_MAX}
characters (which has the minimum value
{_POSIX_TRACE_EVENT_NAME_MAX}).
The number of user trace event type identifiers that can be defined for
any given process is limited by the maximum value
{TRACE_USER_EVENT_MAX},
which has the minimum value
{_POSIX_TRACE_USER_EVENT_MAX}.
.P
If the Trace Inherit option is not supported, the
\fIposix_trace_trid_eventid_open\fR()
function shall associate the user trace event name pointed to by the
.IR event_name
argument with a trace event type identifier that is unique for the
process being traced in the trace stream identified by the
.IR trid
argument, and is returned in the variable pointed to by the
.IR event
argument. If the user trace event name has already been mapped for the
traced process, then the previously assigned trace event type
identifier shall be returned. If the per-process user trace event name
limit represented by
{TRACE_USER_EVENT_MAX}
has been reached, the pre-defined POSIX_TRACE_UNNAMED_USEREVENT (see
.IR "Table 2-7" ", " "Trace Option: User Trace Event")
user trace event shall be returned.
.P
If the Trace Inherit option is supported, the
\fIposix_trace_trid_eventid_open\fR()
function shall associate the user trace event name pointed to by the
.IR event_name
argument with a trace event type identifier that is unique for all the
processes being traced in the trace stream identified by the
.IR trid
argument, and is returned in the variable pointed to by the
.IR event
argument. If the user trace event name has already been mapped for the
traced processes, then the previously assigned trace event type
identifier shall be returned. If the per-process user trace event name
limit represented by
{TRACE_USER_EVENT_MAX}
has been reached, the pre-defined POSIX_TRACE_UNNAMED_USEREVENT (see
.IR "Table 2-7" ", " "Trace Option: User Trace Event")
user trace event shall be returned.
.SH "RETURN VALUE"
Upon successful completion, the
\fIposix_trace_eventid_get_name\fR()
and
\fIposix_trace_trid_eventid_open\fR()
functions shall return a value of zero. Otherwise, they shall return
the corresponding error number.
.P
The
\fIposix_trace_eventid_equal\fR()
function shall return a non-zero value if
.IR event1
and
.IR event2
are equal; otherwise, a value of zero shall be returned. No errors are
defined. If either
.IR event1
or
.IR event2
are not valid trace event type identifiers for the trace stream
specified by
.IR trid
or if the
.IR trid
is invalid, the behavior shall be unspecified.
.P
The
\fIposix_trace_eventid_get_name\fR()
function stores the trace event name value in the object pointed to by
.IR event_name ,
if successful.
.P
The
\fIposix_trace_trid_eventid_open\fR()
function stores the trace event type identifier value in the object
pointed to by
.IR event ,
if successful.
.SH ERRORS
The
\fIposix_trace_eventid_get_name\fR()
and
\fIposix_trace_trid_eventid_open\fR()
functions shall fail if:
.TP
.BR EINVAL
The
.IR trid
argument was not a valid trace stream identifier.
.P
The
\fIposix_trace_trid_eventid_open\fR()
function shall fail if:
.TP
.BR ENAMETOOLONG
.br
The size of the name pointed to by the
.IR event_name
argument was longer than the implementation-defined value
{TRACE_EVENT_NAME_MAX}.
.P
The
\fIposix_trace_eventid_get_name\fR()
function shall fail if:
.TP
.BR EINVAL
The trace event type identifier
.IR event
was not associated with any name.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
The
\fIposix_trace_eventid_equal\fR(),
\fIposix_trace_eventid_get_name\fR(),
and
\fIposix_trace_trid_eventid_open\fR()
functions may be removed in a future version.
.SH "SEE ALSO"
.ad l
.IR "Table 2-7" ", " "Trace Option: User Trace Event",
.IR "\fIexec\fR\^",
.IR "\fIposix_trace_event\fR\^(\|)",
.IR "\fIposix_trace_getnext_event\fR\^(\|)"
.ad b
.P
The Base Definitions volume of POSIX.1\(hy2008,
.IR "\fB<trace.h>\fP"
.SH 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 .

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