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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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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.1‐2017, sys_types.h(0p),
trace.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 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 .
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 2017 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)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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