mtx_timedlock()
Lock a mutex, with a time limit
Synopsis:
#include <threads.h>
#include <time.h>
int mtx_timedlock( mtx_t *mutex,
const struct timespec * ts );
Arguments:
- mutex
- The mutex that you want to lock.
- ts
- A pointer to a timespec structure that specifies the absolute time at which the time-out is to expire.
Library:
libc
Use the -l c option to qcc to link against this library. This library is usually included automatically.
Description:
The mtx_timedlock() function locks the mutex object referenced by mutex. If the mutex is already locked, the calling thread blocks until the mutex becomes available as in mtx_lock(). If the mutex can't be locked without waiting for another thread to unlock the mutex, the wait is terminated when the specified timeout expires.
By default, if a thread with a higher priority than the mutex owner
attempts to lock a mutex, then the effective priority of the current owner is increased to that of the
higher-priority blocked thread waiting for the mutex.
The owner returns to its real priority when it unlocks the mutex.
For more information, see
Mutexes: mutual exclusion locks
in the IDE Microkernel chapter of the System Architecture guide.
The timeout expires when the absolute time specified by ts passes, as measured by the clock on which timeouts are based (i.e., when the value of that clock equals or exceeds ts), or if the absolute time specified by ts has already been passed at the time of the call.
If the mutex can be locked immediately, the validity of the ts parameter isn't checked, and the function won't fail with a timeout.
Returns:
- thrd_success
- Success.
- thrd_error
- An error occurred.
- thrd_timedout
- The mutex couldn't be locked before the specified timeout expired.
Classification:
| Safety: | |
|---|---|
| Cancellation point | No |
| Signal handler | No |
| Thread | Yes |