pthread_rwlockattr

Get the clock attribute from a read-write lock attribute object

Synopsis:

#include <pthread.h>

int pthread_rwlockattr_getclock( 
                     const pthread_rwlockattr_t *attr,
                     clockid_t *id );

Arguments:

attr: A pointer to the pthread_rwlockattr_t object from which you want to get the clock.
id: A pointer to a clockid_t object where the function can store the clock ID.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The pthread_rwlockattr_getclock() function obtains the value of the clock attribute from the attributes object referenced by attr.

The clock attribute is the clock ID of the clock that's used (as a QNX Neutrino extension) to measure the timeout service of pthread_rwlock_timedrdlock() or pthread_rwlock_timedwrlock(); one of:

CLOCK_REALTIME — the standard POSIX-defined clock. Timers based on this clock wake up the processor if it's in a power-saving mode.
CLOCK_SOFTTIME — (a QNX Neutrino extension) this clock is active only when the processor isn't in a power-saving mode. For example, an application using a CLOCK_SOFTTIME timer to sleep wouldn't wake up the processor when the application was due to wake up. This will allow the processor to enter a power-saving mode.
While the processor isn't in a power-saving mode, CLOCK_SOFTTIME behaves the same as CLOCK_REALTIME.
CLOCK_MONOTONIC — this clock always increases at a constant rate and can't be adjusted.

The default value of the clock attribute is CLOCK_REALTIME. For more information about the different clocks, see “Other clock sources” in the Clocks, Timers, and Getting a Kick Every So Often chapter of Getting Started with QNX Neutrino.

Returns:

EOK: Success.

Classification:

QNX Neutrino

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes