PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

POSIX_TRACE_CREATE(3P)    POSIX Programmer's Manual   POSIX_TRACE_CREATE(3P)

PROLOG         top

       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.

NAME         top

       posix_trace_create, posix_trace_create_withlog, posix_trace_flush,
       posix_trace_shutdown — trace stream initialization, flush, and
       shutdown from a process (TRACING)

SYNOPSIS         top

       #include <sys/types.h>
       #include <trace.h>

       int posix_trace_create(pid_t pid,
           const trace_attr_t *restrict attr,
           trace_id_t *restrict trid);
       int posix_trace_create_withlog(pid_t pid,
           const trace_attr_t *restrict attr, int file_desc,
           trace_id_t *restrict trid);
       int posix_trace_flush(trace_id_t trid);
       int posix_trace_shutdown(trace_id_t trid);

DESCRIPTION         top

       The posix_trace_create() function shall create an active trace
       stream. It allocates all the resources needed by the trace stream
       being created for tracing the process specified by pid in accordance
       with the attr argument. The attr argument represents the initial
       attributes of the trace stream and shall have been initialized by the
       function posix_trace_attr_init() prior to the posix_trace_create()
       call. If the argument attr is NULL, the default attributes shall be
       used. The attr attributes object shall be manipulated through a set
       of functions described in the posix_trace_attr family of functions.
       If the attributes of the object pointed to by attr are modified
       later, the attributes of the trace stream shall not be affected. The
       creation-time attribute of the newly created trace stream shall be
       set to the value of the system clock, if the Timers option is not
       supported, or to the value of the CLOCK_REALTIME clock, if the Timers
       option is supported.

       The pid argument represents the target process to be traced. If the
       process executing this function does not have appropriate privileges
       to trace the process identified by pid, an error shall be returned.
       If the pid argument is zero, the calling process shall be traced.

       The posix_trace_create() function shall store the trace stream
       identifier of the new trace stream in the object pointed to by the
       trid argument. This trace stream identifier shall be used in
       subsequent calls to control tracing. The trid argument may only be
       used by the following functions:

       posix_trace_clear()                      posix_trace_getnext_event()
       posix_trace_eventid_equal()              posix_trace_shutdown()
       posix_trace_eventid_get_name()           posix_trace_start()
       posix_trace_eventtypelist_getnext_id()   posix_trace_stop()
       posix_trace_eventtypelist_rewind()       posix_trace_timedgetnext_event()
       posix_trace_get_attr()                   posix_trace_trid_eventid_open()
       posix_trace_get_status()                 posix_trace_trygetnext_event()

       If the Trace Event Filter option is supported, the following
       additional functions may use the trid argument:

       posix_trace_get_filter()   posix_trace_set_filter()

       In particular, notice that the operations normally used by a trace
       analyzer process, such as posix_trace_rewind() or
       posix_trace_close(), cannot be invoked using the trace stream
       identifier returned by the posix_trace_create() function.

       A trace stream shall be created in a suspended state.  If the Trace
       Event Filter option is supported, its trace event type filter shall
       be empty.

       The posix_trace_create() function may be called multiple times from
       the same or different processes, with the system-wide limit indicated
       by the runtime invariant value {TRACE_SYS_MAX}, which has the minimum
       value {_POSIX_TRACE_SYS_MAX}.

       The trace stream identifier returned by the posix_trace_create()
       function in the argument pointed to by trid is valid only in the
       process that made the function call. If it is used from another
       process, that is a child process, in functions defined in
       POSIX.1‐2008, these functions shall return with the error [EINVAL].

       The posix_trace_create_withlog() function shall be equivalent to
       posix_trace_create(), except that it associates a trace log with this
       stream. The file_desc argument shall be the file descriptor
       designating the trace log destination. The function shall fail if
       this file descriptor refers to a file with a file type that is not
       compatible with the log policy associated with the trace log. The
       list of the appropriate file types that are compatible with each log
       policy is implementation-defined.

       The posix_trace_create_withlog() function shall return in the
       parameter pointed to by trid the trace stream identifier, which
       uniquely identifies the newly created trace stream, and shall be used
       in subsequent calls to control tracing. The trid argument may only be
       used by the following functions:

       posix_trace_clear()                      posix_trace_get_status()
       posix_trace_eventid_equal()              posix_trace_getnext_event()
       posix_trace_eventid_get_name()           posix_trace_shutdown()
       posix_trace_eventtypelist_getnext_id()   posix_trace_start()
       posix_trace_eventtypelist_rewind()       posix_trace_stop()
       posix_trace_flush()                      posix_trace_timedgetnext_event()
       posix_trace_get_attr()                   posix_trace_trid_eventid_open()

       If the Trace Event Filter option is supported, the following
       additional functions may use the trid argument:

       posix_trace_get_filter()   posix_trace_set_filter()

       In particular, notice that the operations normally used by a trace
       analyzer process, such as posix_trace_rewind() or
       posix_trace_close(), cannot be invoked using the trace stream
       identifier returned by the posix_trace_create_withlog() function.

       The posix_trace_flush() function shall initiate a flush operation
       which copies the contents of the trace stream identified by the
       argument trid into the trace log associated with the trace stream at
       the creation time. If no trace log has been associated with the trace
       stream pointed to by trid, this function shall return an error. The
       termination of the flush operation can be polled by the
       posix_trace_get_status() function. During the flush operation, it
       shall be possible to trace new trace events up to the point when the
       trace stream becomes full.  After flushing is completed, the space
       used by the flushed trace events shall be available for tracing new
       trace events.

       If flushing the trace stream causes the resulting trace log to become
       full, the trace log full policy shall be applied. If the trace log-
       full-policy attribute is set, the following occurs:

       POSIX_TRACE_UNTIL_FULL
             The trace events that have not yet been flushed shall be
             discarded.

       POSIX_TRACE_LOOP
             The trace events that have not yet been flushed shall be
             written to the beginning of the trace log, overwriting previous
             trace events stored there.

       POSIX_TRACE_APPEND
             The trace events that have not yet been flushed shall be
             appended to the trace log.

       The posix_trace_shutdown() function shall stop the tracing of trace
       events in the trace stream identified by trid, as if
       posix_trace_stop() had been invoked. The posix_trace_shutdown()
       function shall free all the resources associated with the trace
       stream.

       The posix_trace_shutdown() function shall not return until all the
       resources associated with the trace stream have been freed. When the
       posix_trace_shutdown() function returns, the trid argument becomes an
       invalid trace stream identifier. A call to this function shall
       unconditionally deallocate the resources regardless of whether all
       trace events have been retrieved by the analyzer process.  Any thread
       blocked on one of the trace_getnext_event() functions (which
       specified this trid) before this call is unblocked with the error
       [EINVAL].

       If the process exits, invokes a member of the exec family of
       functions, or is terminated, the trace streams that the process had
       created and that have not yet been shut down, shall be automatically
       shut down as if an explicit call were made to the
       posix_trace_shutdown() function.

       For an active trace stream with log, when the posix_trace_shutdown()
       function is called, all trace events that have not yet been flushed
       to the trace log shall be flushed, as in the posix_trace_flush()
       function, and the trace log shall be closed.

       When a trace log is closed, all the information that may be retrieved
       later from the trace log through the trace interface shall have been
       written to the trace log. This information includes the trace
       attributes, the list of trace event types (with the mapping between
       trace event names and trace event type identifiers), and the trace
       status.

       In addition, unspecified information shall be written to the trace
       log to allow detection of a valid trace log during the
       posix_trace_open() operation.

       The posix_trace_shutdown() function shall not return until all trace
       events have been flushed.

RETURN VALUE         top

       Upon successful completion, these functions shall return a value of
       zero. Otherwise, they shall return the corresponding error number.

       The posix_trace_create() and posix_trace_create_withlog() functions
       store the trace stream identifier value in the object pointed to by
       trid, if successful.

ERRORS         top

       The posix_trace_create() and posix_trace_create_withlog() functions
       shall fail if:

       EAGAIN No more trace streams can be started now.  {TRACE_SYS_MAX} has
              been exceeded.

       EINTR  The operation was interrupted by a signal. No trace stream was
              created.

       EINVAL One or more of the trace parameters specified by the attr
              parameter is invalid.

       ENOMEM The implementation does not currently have sufficient memory
              to create the trace stream with the specified parameters.

       EPERM  The caller does not have appropriate privileges to trace the
              process specified by pid.

       ESRCH  The pid argument does not refer to an existing process.

       The posix_trace_create_withlog() function shall fail if:

       EBADF  The file_desc argument is not a valid file descriptor open for
              writing.

       EINVAL The file_desc argument refers to a file with a file type that
              does not support the log policy associated with the trace log.

       ENOSPC No space left on device. The device corresponding to the
              argument file_desc does not contain the space required to
              create this trace log.

       The posix_trace_flush() and posix_trace_shutdown() functions shall
       fail if:

       EINVAL The value of the trid argument does not correspond to an
              active trace stream with log.

       EFBIG  The trace log file has attempted to exceed an implementation-
              defined maximum file size.

       ENOSPC No space left on device.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       The posix_trace_create(), posix_trace_create_withlog(),
       posix_trace_flush(), and posix_trace_shutdown() functions may be
       removed in a future version.

SEE ALSO         top

       clock_getres(3p), exec(1p), posix_trace_attr_destroy(3p),
       posix_trace_clear(3p), posix_trace_close(3p),
       posix_trace_eventid_equal(3p),
       posix_trace_eventtypelist_getnext_id(3p), posix_trace_get_attr(3p),
       posix_trace_get_filter(3p), posix_trace_getnext_event(3p),
       posix_trace_start(3p), posix_trace_start(3p), time(3p)

       The   Base   Definitions  volume  of  POSIX.1‐2008,  sys_types.h(0p),
       trace.h(0p)

COPYRIGHT         top

       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_CREATE(3P)

Pages that refer to this page: trace.h(0p)exec(3p)_Exit(3p)posix_trace_attr_destroy(3p)posix_trace_attr_getclockres(3p)posix_trace_attr_getinherited(3p)posix_trace_attr_getlogsize(3p)posix_trace_clear(3p)posix_trace_flush(3p)posix_trace_get_attr(3p)posix_trace_getnext_event(3p)posix_trace_shutdown(3p)posix_trace_start(3p)