1POSIX_TRACE_EVENT(3P) POSIX Programmer's Manual POSIX_TRACE_EVENT(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
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13 posix_trace_event, posix_trace_eventid_open — trace functions for
14 instrumenting application code (TRACING)
15
17 #include <sys/types.h>
18 #include <trace.h>
19 void posix_trace_event(trace_event_id_t event_id,
21 const void *restrict data_ptr, size_t data_len);
22 int posix_trace_eventid_open(const char *restrict event_name,
23 trace_event_id_t *restrict event_id);
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26 The posix_trace_event() function shall record the event_id and the user
27 data pointed to by data_ptr in the trace stream into which the calling
28 process is being traced and in which event_id is not filtered out. If
29 the total size of the user trace event data represented by data_len is
30 not greater than the declared maximum size for user trace event data,
31 then the truncation-status attribute of the trace event recorded is
32 POSIX_TRACE_NOT_TRUNCATED. Otherwise, the user trace event data is
33 truncated to this declared maximum size and the truncation-status
34 attribute of the trace event recorded is POSIX_TRACE_TRUNCATED_RECORD.
35 If there is no trace stream created for the process or if the created
37 trace stream is not running, or if the trace event specified by
38 event_id is filtered out in the trace stream, the posix_trace_event()
39 function shall have no effect.
40 The posix_trace_eventid_open() function shall associate a user trace
42 event name with a trace event type identifier for the calling process.
43 The trace event name is the string pointed to by the argument
44 event_name. It shall have a maximum of {TRACE_EVENT_NAME_MAX} charac‐
45 ters (which has the minimum value {_POSIX_TRACE_EVENT_NAME_MAX}). The
46 number of user trace event type identifiers that can be defined for any
47 given process is limited by the maximum value {TRACE_USER_EVENT_MAX},
48 which has the minimum value {POSIX_TRACE_USER_EVENT_MAX}.
49 If the Trace Inherit option is not supported, the posix_trace_even‐
51 tid_open() function shall associate the user trace event name pointed
52 to by the event_name argument with a trace event type identifier that
53 is unique for the traced process, and is returned in the variable
54 pointed to by the event_id argument. If the user trace event name has
55 already been mapped for the traced process, then the previously
56 assigned trace event type identifier shall be returned. If the per-
57 process user trace event name limit represented by
58 {TRACE_USER_EVENT_MAX} has been reached, the pre-defined
59 POSIX_TRACE_UNNAMED_USEREVENT (see Table 2-7, Trace Option: User Trace
60 Event) user trace event shall be returned.
61 If the Trace Inherit option is supported, the posix_trace_even‐
63 tid_open() function shall associate the user trace event name pointed
64 to by the event_name argument with a trace event type identifier that
65 is unique for all the processes being traced in this same trace stream,
66 and is returned in the variable pointed to by the event_id argument. If
67 the user trace event name has already been mapped for the traced pro‐
68 cesses, then the previously assigned trace event type identifier shall
69 be returned. If the per-process user trace event name limit represented
70 by {TRACE_USER_EVENT_MAX} has been reached, the pre-defined
71 POSIX_TRACE_UNNAMED_USEREVENT (Table 2-7, Trace Option: User Trace
72 Event) user trace event shall be returned.
73 Note: The above procedure, together with the fact that multiple
75 processes can only be traced into the same trace stream by
76 inheritance, ensure that all the processes that are traced
77 into a trace stream have the same mapping of trace event
78 names to trace event type identifiers.
79 If there is no trace stream created, the posix_trace_eventid_open()
81 function shall store this information for future trace streams created
82 for this process.
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85 No return value is defined for the posix_trace_event() function.
86 Upon successful completion, the posix_trace_eventid_open() function
88 shall return a value of zero. Otherwise, it shall return the corre‐
89 sponding error number. The posix_trace_eventid_open() function stores
90 the trace event type identifier value in the object pointed to by
91 event_id, if successful.
92
94 The posix_trace_eventid_open() function shall fail if:
95 ENAMETOOLONG
97 The size of the name pointed to by the event_name argument was
98 longer than the implementation-defined value
99 {TRACE_EVENT_NAME_MAX}.
100 The following sections are informative.
102
104 None.
105
107 None.
108
110 None.
111
113 The posix_trace_event() and posix_trace_eventid_open() functions may be
114 removed in a future version.
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117 Table 2-7, Trace Option: User Trace Event, exec, posix_trace_even‐
118 tid_equal(), posix_trace_start()
119 The Base Definitions volume of POSIX.1‐2008, <sys_types.h>, <trace.h>
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123 Portions of this text are reprinted and reproduced in electronic form
124 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
125 -- Portable Operating System Interface (POSIX), The Open Group Base
126 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
127 cal and Electronics Engineers, Inc and The Open Group. (This is
128 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
129 event of any discrepancy between this version and the original IEEE and
130 The Open Group Standard, the original IEEE and The Open Group Standard
131 is the referee document. The original Standard can be obtained online
132 at http://www.unix.org/online.html .
133 Any typographical or formatting errors that appear in this page are
135 most likely to have been introduced during the conversion of the source
136 files to man page format. To report such errors, see https://www.ker‐
137 nel.org/doc/man-pages/reporting_bugs.html .
138IEEE/The Open Group 2013 POSIX_TRACE_EVENT(3P)