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Annotation of researchv9/X11/src/X.V11R1/lib/X/XNextEvent.c, revision 1.1

1.1     ! root        1: #include "copyright.h"
        !             2: 
        !             3: /* $Header: XNextEvent.c,v 11.13 87/09/11 08:05:18 toddb Exp $ */
        !             4: /* Copyright    Massachusetts Institute of Technology    1986  */
        !             5: 
        !             6: #define NEED_EVENTS
        !             7: #include "Xlibint.h"
        !             8: 
        !             9: extern _XQEvent *_qfree;
        !            10: 
        !            11: /* 
        !            12:  *Flush output and (wait for and) return the next event in the queue.
        !            13:  */
        !            14: 
        !            15: XNextEvent (dpy, event)
        !            16:        register Display *dpy;
        !            17:        register XEvent *event;
        !            18: {
        !            19:        register _XQEvent *qelt;
        !            20:        
        !            21:        LockDisplay(dpy);
        !            22:        _XFlush (dpy);
        !            23:        
        !            24:        /* if the queue is empty, read as many events as possible
        !            25:           and enqueue them */
        !            26:        while (dpy->head == NULL) {
        !            27:            char buf[BUFSIZE];
        !            28:            long pend_not_register; /* because can't "&" a register variable */
        !            29:            register long pend;
        !            30:            register xEvent *ev;
        !            31: 
        !            32:            /* find out how much data can be read */
        !            33:            if (BytesReadable(dpy->fd, (char *) &pend_not_register) < 0)
        !            34:                (*_XIOErrorFunction)(dpy);
        !            35:            pend = pend_not_register;
        !            36: 
        !            37:            /* must read at least one xEvent; if none is pending, then
        !            38:               we'll just block waiting for it */
        !            39:            if (pend < sizeof(xEvent))
        !            40:                pend = sizeof (xEvent);
        !            41:                
        !            42:            /* but we won't read more than the max buffer size */
        !            43:            if (pend > BUFSIZE)
        !            44:                pend = BUFSIZE;
        !            45: 
        !            46:            /* round down to an integral number of XReps */
        !            47:            pend = (pend / sizeof (xEvent)) * sizeof (xEvent);
        !            48: 
        !            49:            _XRead (dpy, buf, pend);
        !            50:            for (ev = (xEvent *) buf; pend > 0; ev++, pend -= sizeof(xEvent))
        !            51:                if (ev->u.u.type == X_Error)
        !            52:                    _XError (dpy, (xError *) ev);
        !            53:                else  /* it's an event packet; enqueue it */
        !            54:                    _XEnq (dpy, ev);
        !            55:            }
        !            56: 
        !            57:        *event = (qelt = dpy->head)->event;
        !            58: 
        !            59:        /* move the head of the queue to the free list */
        !            60:        if ((dpy->head = qelt->next) == NULL)
        !            61:            dpy->tail = NULL;
        !            62:        qelt->next = _qfree;
        !            63:        _qfree = qelt;
        !            64:        dpy->qlen--;
        !            65:        UnlockDisplay(dpy);
        !            66:        return;
        !            67: }
        !            68: 

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