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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
POSIX_TRACE_EVENT(3P) POSIX Programmer's Manual POSIX_TRACE_EVENT(3P)
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.
posix_trace_event, posix_trace_eventid_open — trace functions for
instrumenting application code (TRACING)
#include <sys/types.h>
#include <trace.h>
void posix_trace_event(trace_event_id_t event_id,
const void *restrict data_ptr, size_t data_len);
int posix_trace_eventid_open(const char *restrict event_name,
trace_event_id_t *restrict event_id);
The posix_trace_event() function shall record the event_id and the
user data pointed to by data_ptr in the trace stream into which the
calling process is being traced and in which event_id is not filtered
out. If the total size of the user trace event data represented by
data_len is not greater than the declared maximum size for user trace
event data, then the truncation-status attribute of the trace event
recorded is POSIX_TRACE_NOT_TRUNCATED. Otherwise, the user trace
event data is truncated to this declared maximum size and the
truncation-status attribute of the trace event recorded is
POSIX_TRACE_TRUNCATED_RECORD.
If there is no trace stream created for the process or if the created
trace stream is not running, or if the trace event specified by
event_id is filtered out in the trace stream, the posix_trace_event()
function shall have no effect.
The posix_trace_eventid_open() function shall associate a user trace
event name with a trace event type identifier for the calling
process. The trace event name is the string pointed to by the
argument 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}.
If the Trace Inherit option is not supported, the
posix_trace_eventid_open() function shall associate the user trace
event name pointed to by the event_name argument with a trace event
type identifier that is unique for the traced process, and is
returned in the variable pointed to by the event_id 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 Table 2-7, Trace Option: User
Trace Event) user trace event shall be returned.
If the Trace Inherit option is supported, the
posix_trace_eventid_open() function shall associate the user trace
event name pointed to by the event_name argument with a trace event
type identifier that is unique for all the processes being traced in
this same trace stream, and is returned in the variable pointed to by
the event_id 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 (Table 2-7,
Trace Option: User Trace Event) user trace event shall be returned.
Note: The above procedure, together with the fact that multiple
processes can only be traced into the same trace stream by
inheritance, ensure that all the processes that are traced
into a trace stream have the same mapping of trace event
names to trace event type identifiers.
If there is no trace stream created, the posix_trace_eventid_open()
function shall store this information for future trace streams
created for this process.
No return value is defined for the posix_trace_event() function.
Upon successful completion, the posix_trace_eventid_open() function
shall return a value of zero. Otherwise, it shall return the
corresponding error number. The posix_trace_eventid_open() function
stores the trace event type identifier value in the object pointed to
by event_id, if successful.
The posix_trace_eventid_open() function shall fail if:
ENAMETOOLONG
The size of the name pointed to by the event_name argument was
longer than the implementation-defined value
{TRACE_EVENT_NAME_MAX}.
The following sections are informative.
None.
None.
None.
The posix_trace_event() and posix_trace_eventid_open() functions may
be removed in a future version.
Table 2-7, Trace Option: User Trace Event, exec(1p),
posix_trace_eventid_equal(3p), posix_trace_start(3p)
The Base Definitions volume of POSIX.1‐2008, sys_types.h(0p),
trace.h(0p)
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 .
IEEE/The Open Group 2013 POSIX_TRACE_EVENT(3P)
Pages that refer to this page: trace.h(0p), exec(3p), posix_trace_attr_getlogsize(3p), posix_trace_eventid_equal(3p), posix_trace_eventid_open(3p), posix_trace_eventtypelist_getnext_id(3p)