CEEOPWT
C library interface: pthread_rwlock_trywrlock()
CEEOPWT conditionally acquires (locks) the read-write lock for
write referred to by rwlock. Conditionally
means the call always returns immediately, whether or not the lock
is acquired. If the read-write lock is already locked, the read-write
lock is not acquired. When successful, this function returns with
the read-write lock in the locked state with the calling thread as
its owner.
Note: Only the owning thread (the thread that acquired
a read-write lock) can unlock it.
Syntax
void CEEOPWT (rwlock,
[fc])
CEE_RWLOCK *rwlock;
FEED_BACK *fc;- CEEOPWT
- Call this CWI interface as follows:
L R15,CEECAALEOV-CEECAA(,R12) CAA address is in R12 L R15,512(,R15) BALR R14,R15 - rwlock (input)
- The read-write lock to be locked for write conditionally.
- fc (output/optional)
- The feedback code returned by the service. It indicates the degree of success in locking the read-write lock for write conditionally.
The following message identifiers and associated severities can be returned by the service in the feedback code fc.
| Condition | Description category | Description value |
|---|---|---|
| CEE000 | Severity | 0 |
| Msg_No | 0000 | |
| Message | The service completed successfully. | |
| CEE4S9 | Severity | 3 |
| Msg_No | 5001 | |
| Message | The service is unavailable unless POSIX(ON) runtime option specified and z/OS UNIX System Services are started. | |
| CEE5K4 | Severity | 3 |
| Msg_No | 5764 | |
| Message | The read-write lock specified by the rwlock was not initialized. | |
| CEE5K6 | Severity | 3 |
| Msg_No | 5766 | |
| Message | An addressing exception occurred referencing a lock object. | |
| CEE5K7 | Severity | 4 |
| Msg_No | 5767 | |
| Message | Address exception while referencing system storage allocated by lock object initialization. | |
| CEE5KN | Severity | 4 |
| Msg_No | 5783 | |
| Message | Read-write lock specified by rwlock was not locked because thread was forced to terminate. | |
| CEE5KQ | Severity | 3 |
| Msg_No | 5786 | |
| Message | The callable service BPX1SLK failed during shared lock processing. The system return code was return_code, the reason code was reason_code, X'00'. | |
| CEE5KT | Severity | 1 |
| Msg_No | 5785 | |
| Message | The read-write lock specified by rwlock was busy. | |
| CEE5KU | Severity | 3 |
| Msg_No | 5790 | |
| Message | Insufficient storage to lock the read-write lock object specified by rwlock. | |
| CEE5KV | Severity | 4 |
| Msg_No | 5791 | |
| Message | System read-write lock storage could not be freed. |
Usage notes:
- The routine to be executed was previously established by the pthread_cleanup_push() (CEEOPCPO) function.
- It is assumed that routine is currently available and does not require an explicit LOAD performed.