PTHREAD_RWLOCK_UNLOCK(3)   POSIX Programmer's Manual  PTHREAD_RWLOCK_UNLOCK(3)



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

NNAAMMEE
       pthread_rwlock_unlock -- unlock a read-write lock object

SSYYNNOOPPSSIISS
       #include <pthread.h>

       int pthread_rwlock_unlock(pthread_rwlock_t *_r_w_l_o_c_k);

DDEESSCCRRIIPPTTIIOONN
       The _p_t_h_r_e_a_d___r_w_l_o_c_k___u_n_l_o_c_k() function shall release a lock held on the
       read-write lock object referenced by _r_w_l_o_c_k.  Results are undefined if
       the read-write lock _r_w_l_o_c_k is not held by the calling thread.

       If this function is called to release a read lock from the read-write
       lock object and there are other read locks currently held on this read-
       write lock object, the read-write lock object remains in the read
       locked state. If this function releases the last read lock for this
       read-write lock object, the read-write lock object shall be put in the
       unlocked state with no owners.

       If this function is called to release a write lock for this read-write
       lock object, the read-write lock object shall be put in the unlocked
       state.

       If there are threads blocked on the lock when it becomes available, the
       scheduling policy shall determine which thread(s) shall acquire the
       lock.  If the Thread Execution Scheduling option is supported, when
       threads executing with the scheduling policies SCHED_FIFO, SCHED_RR, or
       SCHED_SPORADIC are waiting on the lock, they shall acquire the lock in
       priority order when the lock becomes available. For equal priority
       threads, write locks shall take precedence over read locks.  If the
       Thread Execution Scheduling option is not supported, it is
       implementation-defined whether write locks take precedence over read
       locks.

       Results are undefined if this function is called with an uninitialized
       read-write lock.

RREETTUURRNN VVAALLUUEE
       If successful, the _p_t_h_r_e_a_d___r_w_l_o_c_k___u_n_l_o_c_k() function shall return zero;
       otherwise, an error number shall be returned to indicate the error.

EERRRROORRSS
       The _p_t_h_r_e_a_d___r_w_l_o_c_k___u_n_l_o_c_k() function shall not return an error code of
       [[EEIINNTTRR]].

       _T_h_e _f_o_l_l_o_w_i_n_g _s_e_c_t_i_o_n_s _a_r_e _i_n_f_o_r_m_a_t_i_v_e_.

EEXXAAMMPPLLEESS
       None.

AAPPPPLLIICCAATTIIOONN UUSSAAGGEE
       None.

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

       If an implementation detects that the value specified by the _r_w_l_o_c_k
       argument to _p_t_h_r_e_a_d___r_w_l_o_c_k___u_n_l_o_c_k() refers to a read-write lock object
       for which the current thread does not hold a lock, it is recommended
       that the function should fail and report an [[EEPPEERRMM]] error.

FFUUTTUURREE DDIIRREECCTTIIOONNSS
       None.

SSEEEE AALLSSOO
       _p_t_h_r_e_a_d___r_w_l_o_c_k___d_e_s_t_r_o_y(), _p_t_h_r_e_a_d___r_w_l_o_c_k___r_d_l_o_c_k(),
       _p_t_h_r_e_a_d___r_w_l_o_c_k___t_i_m_e_d_r_d_l_o_c_k(), _p_t_h_r_e_a_d___r_w_l_o_c_k___t_i_m_e_d_w_r_l_o_c_k(),
       _p_t_h_r_e_a_d___r_w_l_o_c_k___t_r_y_w_r_l_o_c_k()

       The Base Definitions volume of POSIX.1-2017, _S_e_c_t_i_o_n _4_._1_2, _M_e_m_o_r_y
       _S_y_n_c_h_r_o_n_i_z_a_t_i_o_n, <<pptthhrreeaadd..hh>>

CCOOPPYYRRIIGGHHTT
       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_UNLOCK(3)
