POSIX_TRACE_EVENTID_OPEN(3) Library Functions Manual POSIX_TRACE_EVENTID_OPEN(3)

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 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 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 V2_chap02(3)) 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 ( V2_chap02(3)) user trace event shall be returned.

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:

The size of the name pointed to by the event_name argument was longer than the implementation-defined value {TRACE_EVENT_NAME_MAX}.

None.

None.

None.

The posix_trace_event () and posix_trace_eventid_open () functions may be removed in a future version.

V2_chap02(3), exec(3), posix_trace_eventid_equal(3), posix_trace_start(3)

XBD <sys/types.h>, <trace.h>

First released in Issue 6. Derived from IEEE Std 1003.1q-2000.

IEEE PASC Interpretation 1003.1 #123 is applied.

IEEE PASC Interpretation 1003.1 #127 is applied, correcting some editorial errors in the names of the posix_trace_eventid_open () function and the event_id argument.

The posix_trace_event () and posix_trace_eventid_open () functions are marked obsolescent.

January 1, 2016 posix.fail