/* $XConsortium: XIfEvent.c,v 11.12 91/01/06 11:46:30 rws Exp $ */ /* Copyright Massachusetts Institute of Technology 1986 */ /* Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of M.I.T. not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. M.I.T. makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty. */ #define NEED_EVENTS #include "Xlibint.h" extern _XQEvent *_qfree; /* * Flush output and (wait for and) return the next event matching the * predicate in the queue. */ XIfEvent (dpy, event, predicate, arg) register Display *dpy; Bool (*predicate)( #if NeedNestedPrototypes Display* /* display */, XEvent* /* event */, char* /* arg */ #endif ); /* function to call */ register XEvent *event; char *arg; { register _XQEvent *qelt, *prev; LockDisplay(dpy); prev = NULL; while (1) { for (qelt = prev ? prev->next : dpy->head; qelt; prev = qelt, qelt = qelt->next) { if ((*predicate)(dpy, &qelt->event, arg)) { *event = qelt->event; if (prev) { if ((prev->next = qelt->next) == NULL) dpy->tail = prev; } else { if ((dpy->head = qelt->next) == NULL) dpy->tail = NULL; } qelt->next = _qfree; _qfree = qelt; dpy->qlen--; UnlockDisplay(dpy); return; } } _XReadEvents(dpy); } }