NAME
pthread_rwlockattr_destroy
pthread_rwlockattr_init —
destroy and initialize the read-write lock attributes
object
SYNOPSIS
#include
<pthread.h>
int pthread_rwlockattr_destroy(pthread_rwlockattr_t *attr); int pthread_rwlockattr_init(pthread_rwlockattr_t *attr);
DESCRIPTION
The pthread_rwlockattr_destroy () function
shall destroy a read-write lock attributes object. A destroyed
attr attributes object can be reinitialized using
pthread_rwlockattr_init (); the results of otherwise
referencing the object after it has been destroyed are undefined. An
implementation may cause pthread_rwlockattr_destroy
() to set the object referenced by attr to an invalid
value.
The pthread_rwlockattr_init () function shall initialize 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 attr 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) shall not affect any previously initialized read-write locks.
The behavior is undefined if the value specified by the
attr argument to
pthread_rwlockattr_destroy () does not refer to an
initialized read-write lock attributes object.
RETURN VALUE
If successful, the
pthread_rwlockattr_destroy () and
pthread_rwlockattr_init () functions shall return zero;
otherwise, an error number shall be returned to indicate the error.
ERRORS
The pthread_rwlockattr_init () function shall fail if:
- [ENOMEM]
- Insufficient memory exists to initialize the read-write lock attributes object.
These functions shall not return an error code of [EINTR].
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
If an implementation detects that the value specified by the
attr argument to
pthread_rwlockattr_destroy () does not refer to an
initialized read-write lock attributes object, it is recommended that the
function should fail and report an [EINVAL] error.
FUTURE DIRECTIONS
None.
SEE ALSO
pthread_rwlock_destroy(3), pthread_rwlockattr_getpshared(3)
XBD <pthread.h>
CHANGE HISTORY
First released in Issue 5.
Issue 6
The following changes are made for alignment with IEEE Std 1003.1j-2000:
- The margin code in the SYNOPSIS is changed to THR to indicate that the functionality is now part of the Threads option (previously it was part of the Read-Write Locks option in IEEE Std 1003.1j-2000 and also part of the XSI extension).
- The SEE ALSO section is updated.
Issue 7
The pthread_rwlockattr_destroy () and
pthread_rwlockattr_init () functions are moved from the
Threads option to the Base.
The [EINVAL] error for an uninitialized read-write lock attributes object is removed; this condition results in undefined behavior.