PROLOG¶

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¶

posix_trace_close, posix_trace_open, posix_trace_rewind — trace log management (TRACING)

SYNOPSIS¶

#include <trace.h>

int posix_trace_close(trace_id_t trid);
int posix_trace_open(int file_desc, trace_id_t *trid);
int posix_trace_rewind(trace_id_t trid);

DESCRIPTION¶

The posix_trace_close() function shall deallocate the trace log identifier indicated by trid, and all of its associated resources. If there is no valid trace log pointed to by the trid, this function shall fail.

The posix_trace_open() function shall allocate the necessary resources and establish the connection between a trace log identified by the file_desc argument and a trace stream identifier identified by the object pointed to by the trid argument. The file_desc argument should be a valid open file descriptor that corresponds to a trace log. The file_desc argument shall be open for reading. The current trace event timestamp, which specifies the timestamp of the trace event that will be read by the next call to posix_trace_getnext_event(), shall be set to the timestamp of the oldest trace event recorded in the trace log identified by trid.

The posix_trace_open() function shall return a trace stream identifier in the variable pointed to by the trid argument, that may only be used by the following functions:

In particular, notice that the operations normally used by a trace controller process, such as posix_trace_start(), posix_trace_stop(), or posix_trace_shutdown(), cannot be invoked using the trace stream identifier returned by the posix_trace_open() function.

The posix_trace_rewind() function shall reset the current trace event timestamp, which specifies the timestamp of the trace event that will be read by the next call to posix_trace_getnext_event(), to the timestamp of the oldest trace event recorded in the trace log identified by trid.

RETURN VALUE¶

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

If successful, the posix_trace_open() function stores the trace stream identifier value in the object pointed to by trid.

ERRORS¶

The posix_trace_open() function shall fail if:

EINTR

The operation was interrupted by a signal and thus no trace log was opened.

EINVAL

The object pointed to by file_desc does not correspond to a valid trace log.

The posix_trace_close() and posix_trace_rewind() functions may fail if:

EINVAL

The object pointed to by trid does not correspond to a valid trace log.

The following sections are informative.

EXAMPLES¶

None.

APPLICATION USAGE¶

None.

RATIONALE¶

None.

FUTURE DIRECTIONS¶

The posix_trace_close(), posix_trace_open(), and posix_trace_rewind() functions may be removed in a future version.

SEE ALSO¶

posix_trace_get_attr(), posix_trace_get_filter(), posix_trace_getnext_event()

The Base Definitions volume of POSIX.1‐2017, <trace.h>

COPYRIGHT¶

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 .