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      1 
      2 /*
      3 
      4 Copyright 1993, 1998  The Open Group
      5 
      6 Permission to use, copy, modify, distribute, and sell this software and its
      7 documentation for any purpose is hereby granted without fee, provided that
      8 the above copyright notice appear in all copies and that both that
      9 copyright notice and this permission notice appear in supporting
     10 documentation.
     11 
     12 The above copyright notice and this permission notice shall be included in
     13 all copies or substantial portions of the Software.
     14 
     15 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
     18 OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
     19 AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     20 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     21 
     22 Except as contained in this notice, the name of The Open Group shall not be
     23 used in advertising or otherwise to promote the sale, use or other dealings
     24 in this Software without prior written authorization from The Open Group.
     25 
     26 */
     27 
     28 /*
     29  * Author: Stephen Gildea, MIT X Consortium
     30  *
     31  * XLockDis.c - multi-thread application-level locking routines
     32  */
     33 
     34 #ifdef HAVE_CONFIG_H
     35 #include <config.h>
     36 #endif
     37 #include "Xlibint.h"
     38 #ifdef XTHREADS
     39 #include "locking.h"
     40 #endif
     41 
     42 void
     43 XLockDisplay(
     44     register Display* dpy)
     45 {
     46 #ifdef XTHREADS
     47     LockDisplay(dpy);
     48     if (dpy->lock)
     49 	(*dpy->lock->user_lock_display)(dpy);
     50     /*
     51      * We want the threads in the reply queue to all get out before
     52      * XLockDisplay returns, in case they have any side effects the
     53      * caller of XLockDisplay was trying to protect against.
     54      * XLockDisplay puts itself at the head of the event waiters queue
     55      * to wait for all the replies to come in.
     56      */
     57     if (dpy->lock && dpy->lock->reply_awaiters) {
     58 	struct _XCVList *cvl;
     59 
     60 	cvl = (*dpy->lock->create_cvl)(dpy);
     61 
     62 	/* stuff ourselves on the head of the queue */
     63 	cvl->next = dpy->lock->event_awaiters;
     64 	dpy->lock->event_awaiters = cvl;
     65 
     66 	while (dpy->lock->reply_awaiters)
     67 	    ConditionWait(dpy, cvl->cv);
     68 	UnlockNextEventReader(dpy); /* pass the signal on */
     69     }
     70     UnlockDisplay(dpy);
     71 #endif
     72 }
     73 
     74 void
     75 XUnlockDisplay(
     76     register Display* dpy)
     77 {
     78 #ifdef XTHREADS
     79     LockDisplay(dpy);
     80     if (dpy->lock)
     81 	(*dpy->lock->user_unlock_display)(dpy);
     82     UnlockDisplay(dpy);
     83 #endif
     84 }
     85