operations

SYNOPSIS

     #include <pthread.h>

     int
     pthread_mutexattr_init(pthread_mutexattr_t *attr);

     int
     pthread_mutexattr_destroy(pthread_mutexattr_t *attr);

     int
     pthread_mutexattr_setprioceiling(pthread_mutexattr_t *attr,
         int prioceiling);

     int
     pthread_mutexattr_getprioceiling(pthread_mutexattr_t *attr,
         int *prioceiling);

     int
     pthread_mutexattr_setprotocol(pthread_mutexattr_t *attr, int protocol);

     int
     pthread_mutexattr_getprotocol(pthread_mutexattr_t *attr, int *protocol);

     int
     pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type);

     int
     pthread_mutexattr_gettype(pthread_mutexattr_t *attr, int *type);

DESCRIPTION

     Mutex attributes are used to specify parameters to pthread_mutex_init().
     One attribute object can be used in multiple calls to
     pthread_mutex_init(), with or without modifications between calls.

     The pthread_mutexattr_init() function initializes attr with all the
     default mutex attributes.

     The pthread_mutexattr_destroy() function destroys attr.

     The pthread_mutexattr_settype() functions set the mutex type value of the
     attribute.  Valid mutex types are: PTHREAD_MUTEX_NORMAL,
     PTHREAD_MUTEX_ERRORCHECK, PTHREAD_MUTEX_RECURSIVE, and
     PTHREAD_MUTEX_DEFAULT.  The default mutex type for
     pthread_mutexaddr_init() is PTHREAD_MUTEX_DEFAULT.

     PTHREAD_MUXEX_NORMAL mutexes do not check for usage errors.
     PTHREAD_MUTEX_NORMAL mutexes will deadlock if reentered, and result in
     undefined behavior if a locked mutex is unlocked by another thread.
     Attempts to unlock an already unlocked PTHREAD_MUTEX_NORMAL mutex will
     result in undefined behavior.
     that is locked by another thread, an error will be returned.  If a thread
     attemps to unlock a PTHREAD_MUTEX_RECURSIVE thread that is unlocked, an
     error will be returned.

     PTHREAD_MUTEX_DEFAULT mutexes result in undefined behavior if reentered.
     Unlocking a PTHREAD_MUTEX_DEFAULT mutex locked by another thread will
     result in undefined behavior.  Attempts to unlock an already unlocked
     PTHREAD_MUTEX_DEFAULT mutex will result in undefined behavior.

     pthread_mutexattr_gettype() functions copy the type value of the
     attribute to the location pointed to by the second parameter.

     The pthread_mutexattr_set*() functions set the attribute that corresponds
     to each function name.

     The pthread_mutexattr_get*() functions copy the value of the attribute
     that corresponds to each function name to the location pointed to by the
     second function parameter.

RETURN VALUES

     If successful, these functions return 0.  Otherwise, an error number is
     returned to indicate the error.

ERRORS

     pthread_mutexattr_init() will fail if:

     [ENOMEM]           Out of memory.

     pthread_mutexattr_destroy() will fail if:

     [EINVAL]           Invalid value for attr.

     pthread_mutexattr_setprioceiling() will fail if:

     [EINVAL]           Invalid value for attr, or invalid value for
                        prioceiling.

     pthread_mutexattr_getprioceiling() will fail if:

     [EINVAL]           Invalid value for attr.

     pthread_mutexattr_setprotocol() will fail if:

     [EINVAL]           Invalid value for attr, or invalid value for protocol.

     pthread_mutexattr_getprotocol() will fail if:

     [EINVAL]           Invalid value for attr.

     pthread_mutexattr_settype() will fail if:

     [EINVAL]           Invalid value for attr, or invalid value for type.
     pthread_mutexattr_settype(), and pthread_mutexattr_gettype() conform to
     Version 2 of the Single UNIX Specification (``SUSv2'')

BSD                            January 30, 2003                            BSD