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pthread_mutexattr_destroy(3) [netbsd man page]

PTHREAD_MUTEXATTR(3)					   BSD Library Functions Manual 				      PTHREAD_MUTEXATTR(3)

NAME
pthread_mutexattr_init, pthread_mutexattr_destroy, pthread_mutexattr_settype, pthread_mutexattr_gettype -- mutex attribute operations LIBRARY
POSIX Threads Library (libpthread, -lpthread) SYNOPSIS
#include <pthread.h> int pthread_mutexattr_init(pthread_mutexattr_t *attr); int pthread_mutexattr_destroy(pthread_mutexattr_t *attr); int pthread_mutexattr_settype(pthread_mutexattr_t *attr, int type); int pthread_mutexattr_gettype(pthread_mutexattr_t * restrict attr, int * restrict type); DESCRIPTION
Mutex attributes are used to specify parameters to pthread_mutex_init(). Like with thread attributes, one attribute object can be used in multiple calls to pthread_mutex_init(3), 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 This type of mutex does not check for usage errors. It 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. PTHREAD_MUTEX_ERRORCHECK These mutexes do check for usage errors. If an attempt is made to relock a PTHREAD_MUTEX_ERRORCHECK mutex without first dropping the lock, an error will be returned. If a thread attempts to unlock a PTHREAD_MUTEX_ERRORCHECK mutex that is locked by another thread, an error will be returned. If a thread attempts to unlock a PTHREAD_MUTEX_ERRORCHECK thread that is unlocked, an error will be returned. PTHREAD_MUTEX_RECURSIVE These mutexes allow recursive locking. An attempt to relock a PTHREAD_MUTEX_RECURSIVE mutex that is already locked by the same thread succeeds. An equivalent number of pthread_mutex_unlock(3) calls are needed before the mutex will wake another thread waiting on this lock. If a thread attempts to unlock a PTHREAD_MUTEX_RECURSIVE mutex that is locked by another thread, an error will be returned. If a thread attempts to unlock a PTHREAD_MUTEX_RECURSIVE thread that is unlocked, an error will be returned. It is advised that PTHREAD_MUTEX_RECURSIVE mutexes are not used with condition variables. This is because of the implicit unlocking done by pthread_cond_wait(3) and pthread_cond_timedwait(3). PTHREAD_MUTEX_DEFAULT Also this type of mutex will cause 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 behav- ior. This is the default mutex type for pthread_mutexaddr_init(). The pthread_mutexattr_gettype() functions copy the type value of the attribute to the location pointed to by the second parameter. RETURN VALUES
If successful, these functions return 0. Otherwise, an error number is returned to indicate the error. ERRORS
The pthread_mutexattr_init() function shall fail if: [ENOMEM] Insufficient memory exists to initialize the mutex attributes object. The pthread_mutexattr_settype() function shall fail if: [EINVAL] The value specified either by type or attr is invalid. No error numbers are defined for the pthread_mutexattr_destroy() and pthread_mutexattr_gettype() functions. SEE ALSO
pthread_mutex_init(3) STANDARDS
These functions conform to IEEE Std 1003.1-2001 (``POSIX.1''). BSD
July 9, 2010 BSD

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PTHREAD_MUTEXATTR(3)					   BSD Library Functions Manual 				      PTHREAD_MUTEXATTR(3)

NAME
pthread_mutexattr_init, pthread_mutexattr_destroy, pthread_mutexattr_setprioceiling, pthread_mutexattr_getprioceiling, pthread_mutexattr_setprotocol, pthread_mutexattr_getprotocol, pthread_mutexattr_settype, pthread_mutexattr_gettype -- mutex attribute opera- tions 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(). Like with thread attributes, one attribute object can be used in multiple calls to pthread_mutex_init(3), 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 This type of mutex does not check for usage errors. It 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. PTHREAD_MUTEX_ERRORCHECK These mutexes do check for usage errors. If an attempt is made to relock a PTHREAD_MUTEX_ERRORCHECK mutex without first dropping the lock, an error will be returned. If a thread attempts to unlock a PTHREAD_MUTEX_ERRORCHECK mutex that is locked by another thread, an error will be returned. If a thread attempts to unlock a PTHREAD_MUTEX_ERRORCHECK thread that is unlocked, an error will be returned. PTHREAD_MUTEX_RECURSIVE These mutexes allow recursive locking. An attempt to relock a PTHREAD_MUTEX_RECURSIVE mutex that is already locked by the same thread succeeds. An equivalent number of pthread_mutex_unlock(3) calls are needed before the mutex will wake another thread waiting on this lock. If a thread attempts to unlock a PTHREAD_MUTEX_RECURSIVE mutex that is locked by another thread, an error will be returned. If a thread attempts to unlock a PTHREAD_MUTEX_RECURSIVE thread that is unlocked, an error will be returned. It is advised that PTHREAD_MUTEX_RECURSIVE mutexes are not used with condition variables. This is because of the implicit unlocking done by pthread_cond_wait(3) and pthread_cond_timedwait(3). PTHREAD_MUTEX_DEFAULT Also this type of mutex will cause 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 behav- ior. This is the default mutex type for pthread_mutexaddr_init(). 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
The pthread_mutexattr_init() function shall fail if: [ENOMEM] Out of memory. The pthread_mutexattr_destroy() function will fail if: [EINVAL] Invalid value for attr. The pthread_mutexattr_setprioceiling() function will fail if: [EINVAL] Invalid value for attr, or invalid value for prioceiling. The pthread_mutexattr_getprioceiling() function will fail if: [EINVAL] Invalid value for attr. The pthread_mutexattr_setprotocol() function will fail if: [EINVAL] Invalid value for attr, or invalid value for protocol. The pthread_mutexattr_getprotocol() function will fail if: [EINVAL] Invalid value for attr. The pthread_mutexattr_settype() function shall fail if: [EINVAL] The value specified either by type or attr is invalid. The pthread_mutexattr_gettype() function will fail if: [EINVAL] Invalid value for attr. SEE ALSO
pthread_mutex_init(3) STANDARDS
The pthread_mutexattr_init() and pthread_mutexattr_destroy() functions conform to ISO/IEC 9945-1:1996 (``POSIX.1'') The pthread_mutexattr_setprioceiling(), pthread_mutexattr_getprioceiling(), pthread_mutexattr_setprotocol(), pthread_mutexattr_getprotocol(), pthread_mutexattr_settype(), and pthread_mutexattr_gettype() functions conform to Version 2 of the Single UNIX Specification (``SUSv2'') BSD
July 9, 2010 BSD
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