posix_trace_open (3p) - Linux Manuals

posix_trace_open: trace log

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:

posix_trace_close() posix_trace_eventid_equal() posix_trace_eventid_get_name() posix_trace_eventtypelist_getnext_id() posix_trace_eventtypelist_rewind()

posix_trace_get_attr() posix_trace_get_status() posix_trace_getnext_event() posix_trace_rewind()

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

None.

COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .