PTHREAD_CONDATTR_DESTROY(3POSIX)

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
pthread_condattr_destroy, pthread_condattr_init — destroy and initialize the condition variable attributes object

SYNOPSIS

#include <pthread.h>

int pthread_condattr_destroy(pthread_condattr_t *attr);
int pthread_condattr_init(pthread_condattr_t *attr);

DESCRIPTION
The pthread_condattr_destroy() function shall destroy a condition variable attributes object; the object becomes, in effect, uninitialized. An implementation may cause pthread_condattr_destroy() to set the object referenced by attr to an invalid value. A destroyed attr attributes object can be reinitialized using pthread_condattr_init(); the results of otherwise referencing the object after it has been destroyed are undefined.

The pthread_condattr_init() function shall initialize a condition variable attributes object attr with the default value for all of the attributes defined by the implementation.

Results are undefined if pthread_condattr_init() is called specifying an already initialized attr attributes object.

After a condition variable attributes object has been used to initialize one or more condition variables, any function affecting the attributes object (including destruction) shall not affect any previously initialized condition variables.

This volume of POSIX.1-2017 requires two attributes, the clock attribute and the process-shared attribute.

Additional attributes, their default values, and the names of the associated functions to get and set those attribute values are implementation-defined.

The behavior is undefined if the value specified by the attr argument to pthread_condattr_destroy() does not refer to an initialized condition variable attributes object.

RETURN VALUE
If successful, the pthread_condattr_destroy() and pthread_condattr_init() functions shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS
The pthread_condattr_init() function shall fail if:

ENOMEM
    Insufficient memory exists to initialize the condition variable attributes object.

These functions shall not return an error code of [EINTR].

The following sections are informative.

EXAMPLES
None.

APPLICATION USAGE
None.

RATIONALE
A process-shared attribute has been defined for condition variables for the same reason it has been defined for mutexes.

If an implementation detects that the value specified by the attr argument to pthread_condattr_destroy() does not refer to an initialized condition variable attributes object, it is recommended that the function should fail and report an [EINVAL] error.

See also pthread_attr_destroy() and pthread_mutex_destroy().

FUTURE DIRECTIONS
None.

SEE ALSO
pthread_attr_destroy(), pthread_cond_destroy(), pthread_condattr_getpshared(), pthread_create(), pthread_mutex_destroy()

The Base Definitions volume of POSIX.1-2017, <pthread.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 .