Gets and sets process-shared attribute of read-write lock attributes object.
Threads Library (libpthreads.a)
#include <pthread.h> int pthread_rwlockattr_getpshared (attr, pshared) const pthread_rwlockattr_t *attr; int *pshared; int pthread_rwlockattr_setpshared (attr, pshared) pthread_rwlockattr_t *attr; int pshared;
The process-shared attribute is set to PTHREAD_PROCESS_SHARED to permit a read-write lock to be operated upon by any thread that has access to the memory where the read-write lock is allocated, even if the read-write lock is allocated in memory that is shared by multiple processes. If the process-shared attribute is PTHREAD_PROCESS_PRIVATE, the read-write lock will only be operated upon by threads created within the same process as the thread that initialized the read-write lock; if threads of differing processes attempt to operate on such a read-write lock, the behavior is undefined. The default value of the process-shared attribute is PTHREAD_PROCESS_PRIVATE.
The pthread_rwlockattr_getpshared subroutine obtains the value of the process-shared attribute from the initialized attributes object referenced by attr. The pthread_rwlockattr_setpshared subroutine is used to set the process-shared attribute in an initialized attributes object referenced by attr.
| attr | Specifies the initialized attributes object. |
| pshared | Specifies the process-shared attribute of read-write lock attributes object to be gotten and set. |
If successful, the pthread_rwlockattr_setpshared subroutine returns zero. Otherwise, an error number is returned to indicate the error.
Upon successful completion, the pthread_rwlockattr_getpshared subroutine returns zero and stores the value of the process-shared attribute of attr into the object referenced by the pshared parameter. Otherwise an error number is returned to indicate the error.
The pthread_rwlockattr_getpshared and pthread_rwlockattr_setpshared subroutines will fail if:
| EINVAL | The value specified by attr is invalid. |
The pthread_rwlockattr_setpshared subroutine will fail if:
| EINVAL | The new value specified for the attribute is outside the range of legal values for that attribute. |
The pthread.h file.
The pthread_rwlock_init (pthread_rwlock_init or pthread_rwlock_destroy Subroutine), pthread_rwlock_unlock (pthread_rwlock_unlock Subroutine), pthread_rwlock_wrlock (pthread_rwlock_wrlock or pthread_rwlock_trywrlock Subroutines), pthread_rwlock_rdlock (pthread_rwlock_rdlock or pthread_rwlock_tryrdlock Subroutines), pthread_rwlockattr_init (pthread_rwlockattr_init or pthread_rwlockattr_destroy Subroutines) subroutines.