pthread_rwlockattr_init, pthread_rwlockattr_destroy - initialize or destroy read-write lock attributes object
cc –mt [ flag... ] file... [ library... ] #include <pthread.h> int pthread_rwlockattr_init(pthread_rwlockattr_t *attr);
int pthread_rwlockattr_destroy(pthread_rwlockattr_t *attr);
The pthread_rwlockattr_init() function initializes a read-write lock attributes object attr with the default value for all of the attributes defined by the implementation.
Results are undefined if pthread_rwlockattr_init() is called specifying an already initialized read-write lock attributes object.
After a read-write lock attributes object has been used to initialize one or more read-write locks, any function affecting the attributes object (including destruction) does not affect any previously initialized read-write locks.
The pthread_rwlockattr_destroy() function destroys a read-write lock attributes object. The effect of subsequent use of the object is undefined until the object is re-initialized by another call to pthread_rwlockattr_init(). An implementation can cause pthread_rwlockattr_destroy() to set the object referenced by attr to an invalid value.
If successful, the pthread_rwlockattr_init() and pthread_rwlockattr_destroy() functions return 0. Otherwise, an error number is returned to indicate the error.
The pthread_rwlockattr_init() function will fail if:
Insufficient memory exists to initialize the read-write lock attributes object.
The pthread_rwlockattr_destroy() function may fail if:
The value specified by attr is invalid.
See attributes(5) for descriptions of the following attributes: