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(3). The default value of the clock attribute shall refer to the system clock.
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_destroy(3), pthread_cond_timedwait(3), pthread_condattr_destroy(3), pthread_condattr_getpshared(3), pthread_create(3), pthread_mutex_destroy(3)
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.