pthread_rwlock_destroy(3p) — Linux manual page

PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

PTHREAD_RWLOCK_DESTROY(3P)SIX Programmer's ManualREAD_RWLOCK_DESTROY(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       pthread_rwlock_destroy, pthread_rwlock_init — destroy and
       initialize a read-write lock object

SYNOPSIS         top

       #include <pthread.h>

       int pthread_rwlock_destroy(pthread_rwlock_t *rwlock);
       int pthread_rwlock_init(pthread_rwlock_t *restrict rwlock,
           const pthread_rwlockattr_t *restrict attr);
       pthread_rwlock_t rwlock = PTHREAD_RWLOCK_INITIALIZER;

DESCRIPTION         top

       The pthread_rwlock_destroy() function shall destroy the read-
       write lock object referenced by rwlock and release any resources
       used by the lock. The effect of subsequent use of the lock is
       undefined until the lock is reinitialized by another call to
       pthread_rwlock_init().  An implementation may cause
       pthread_rwlock_destroy() to set the object referenced by rwlock
       to an invalid value. Results are undefined if
       pthread_rwlock_destroy() is called when any thread holds rwlock.
       Attempting to destroy an uninitialized read-write lock results in
       undefined behavior.

       The pthread_rwlock_init() function shall allocate any resources
       required to use the read-write lock referenced by rwlock and
       initializes the lock to an unlocked state with attributes
       referenced by attr.  If attr is NULL, the default read-write lock
       attributes shall be used; the effect is the same as passing the
       address of a default read-write lock attributes object. Once
       initialized, the lock can be used any number of times without
       being reinitialized. Results are undefined if
       pthread_rwlock_init() is called specifying an already initialized
       read-write lock. Results are undefined if a read-write lock is
       used without first being initialized.

       If the pthread_rwlock_init() function fails, rwlock shall not be
       initialized and the contents of rwlock are undefined.

       See Section 2.9.9, Synchronization Object Copies and Alternative
       Mappings for further requirements.

       In cases where default read-write lock attributes are
       appropriate, the macro PTHREAD_RWLOCK_INITIALIZER can be used to
       initialize read-write locks. The effect shall be equivalent to
       dynamic initialization by a call to pthread_rwlock_init() with
       the attr parameter specified as NULL, except that no error checks
       are performed.

       The behavior is undefined if the value specified by the attr
       argument to pthread_rwlock_init() does not refer to an
       initialized read-write lock attributes object.

RETURN VALUE         top

       If successful, the pthread_rwlock_destroy() and
       pthread_rwlock_init() functions shall return zero; otherwise, an
       error number shall be returned to indicate the error.

ERRORS         top

       The pthread_rwlock_init() function shall fail if:

       EAGAIN The system lacked the necessary resources (other than
              memory) to initialize another read-write lock.

       ENOMEM Insufficient memory exists to initialize the read-write
              lock.

       EPERM  The caller does not have the privilege to perform the
              operation.

       These functions shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       Applications using these and related read-write lock functions
       may be subject to priority inversion, as discussed in the Base
       Definitions volume of POSIX.1‐2017, Section 3.291, Priority
       Inversion.

RATIONALE         top

       If an implementation detects that the value specified by the
       rwlock argument to pthread_rwlock_destroy() does not refer to an
       initialized read-write lock object, it is recommended that the
       function should fail and report an [EINVAL] error.

       If an implementation detects that the value specified by the attr
       argument to pthread_rwlock_init() does not refer to an
       initialized read-write lock attributes object, it is recommended
       that the function should fail and report an [EINVAL] error.

       If an implementation detects that the value specified by the
       rwlock argument to pthread_rwlock_destroy() or
       pthread_rwlock_init() refers to a locked read-write lock object,
       or detects that the value specified by the rwlock argument to
       pthread_rwlock_init() refers to an already initialized read-write
       lock object, it is recommended that the function should fail and
       report an [EBUSY] error.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       pthread_rwlock_rdlock(3p), pthread_rwlock_timedrdlock(3p),
       pthread_rwlock_timedwrlock(3p), pthread_rwlock_trywrlock(3p),
       pthread_rwlock_unlock(3p)

       The Base Definitions volume of POSIX.1‐2017, Section 3.291,
       Priority Inversion, pthread.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group               2017        PTHREAD_RWLOCK_DESTROY(3P)

Pages that refer to this page: pthread.h(0p)pthread_rwlockattr_destroy(3p)pthread_rwlockattr_getpshared(3p)pthread_rwlock_rdlock(3p)pthread_rwlock_timedrdlock(3p)pthread_rwlock_timedwrlock(3p)pthread_rwlock_trywrlock(3p)pthread_rwlock_unlock(3p)