pthread_condattr_init(3) - Linux man page

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 IEEE Std 1003.1-2001 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.

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_destroy() function may fail if:

EINVAL
The value specified by attr is invalid.

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

See pthread_attr_init() and pthread_mutex_init().

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

Future Directions

None.

See Also

pthread_attr_destroy(), pthread_cond_destroy(), pthread_condattr_getpshared(), pthread_create(), pthread_mutex_destroy(), the Base Definitions volume of IEEE Std 1003.1-2001, <pthread.h>

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 © 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 .