NAME

pthread_condattr_getclock, pthread_condattr_setclock — get and set the clock selection condition variable attribute

SYNOPSIS

#include <pthread.h>

int pthread_condattr_getclock(const pthread_condattr_t *restrict attr,
       clockid_t *restrict clock_id);
int pthread_condattr_setclock(pthread_condattr_t *attr,
       clockid_t clock_id);


DESCRIPTION

The pthread_condattr_getclock() function shall obtain the value of the clock attribute from the attributes object referenced by attr.

The pthread_condattr_setclock() function shall set the clock attribute in an initialized attributes object referenced by attr. If pthread_condattr_setclock() is called with a clock_id argument that refers to a CPU-time clock, the call shall fail.

The clock attribute is the clock ID of the clock that shall be used to measure the timeout service of pthread_cond_timedwait(). The default value of the clock attribute shall refer to the system clock. The clock attribute shall have no effect on the pthread_cond_clockwait() function.

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

RETURN VALUE

If successful, the pthread_condattr_getclock() function shall return zero and store the value of the clock attribute of attr into the object referenced by the clock_id argument. Otherwise, an error number shall be returned to indicate the error.

If successful, the pthread_condattr_setclock() function shall return zero; otherwise, an error number shall be returned to indicate the error.

ERRORS

The pthread_condattr_setclock() function may fail if:

[EINVAL]

The value specified by clock_id does not refer to a known clock, or is a CPU-time clock.

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

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

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

FUTURE DIRECTIONS

None.

SEE ALSO

pthread_cond_clockwait, pthread_cond_destroy, pthread_condattr_destroy, pthread_condattr_getpshared, pthread_create, pthread_mutex_destroy

XBD <pthread.h>

CHANGE HISTORY

First released in Issue 6. Derived from IEEE Std 1003.1j-2000.

Issue 7

The pthread_condattr_getclock() and pthread_condattr_setclock() functions are moved from the Clock Selection option to the Base.

The [EINVAL] error for an uninitialized condition variable attributes object is removed; this condition results in undefined behavior.

Issue 8

Austin Group Defect 1216 is applied, adding pthread_cond_clockwait().