/** * \file miniglx_events.c * \brief Mini GLX client/server communication functions. * \author Keith Whitwell * * The Mini GLX interface is a subset of the GLX interface, plus a * minimal set of Xlib functions. This file adds interfaces to * arbitrate a single cliprect between multiple direct rendering * clients. * * A fairly complete client/server non-blocking communication * mechanism. Probably overkill given that none of our messages * currently exceed 1 byte in length and take place over the * relatively benign channel provided by a Unix domain socket. */ /* * Mesa 3-D graphics library * Version: 5.0 * * Copyright (C) 1999-2003 Brian Paul All Rights Reserved. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included * in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ /* $Id: miniglx_events.c,v 1.1.1.3 2005/10/18 02:51:50 kem Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "xf86drm.h" #include "miniglxP.h" #define MINIGLX_FIFO_NAME "/tmp/miniglx.fifo" /** * \brief Allocate an XEvent structure on the event queue. * * \param dpy the display handle. * * \return Pointer to the queued event structure or NULL on failure. * * \internal * If there is space on the XEvent queue, return a pointer * to the next free event and increment the eventqueue tail value. * Otherwise return null. */ static XEvent *queue_event( Display *dpy ) { int incr = (dpy->eventqueue.tail + 1) & MINIGLX_EVENT_QUEUE_MASK; if (incr == dpy->eventqueue.head) { return 0; } else { XEvent *ev = &dpy->eventqueue.queue[dpy->eventqueue.tail]; dpy->eventqueue.tail = incr; return ev; } } /** * \brief Dequeue an XEvent and copy it into provided storage. * * \param dpy the display handle. * \param event_return pointer to copy the queued event to. * * \return True or False depending on success. * * \internal * If there is a queued XEvent on the queue, copy it to the provided * pointer and increment the eventqueue head value. Otherwise return * null. */ static int dequeue_event( Display *dpy, XEvent *event_return ) { if (dpy->eventqueue.tail == dpy->eventqueue.head) { return False; } else { *event_return = dpy->eventqueue.queue[dpy->eventqueue.head]; dpy->eventqueue.head += 1; dpy->eventqueue.head &= MINIGLX_EVENT_QUEUE_MASK; return True; } } /** * \brief Shutdown a socket connection. * * \param dpy the display handle. * \param i the index in dpy->fd of the socket connection. * * \internal * Shutdown and close the file descriptor. If this is the special * connection in fd[0], issue an error message and exit - there's been * some sort of failure somewhere. Otherwise, let the application * know about whats happened by issuing a DestroyNotify event. */ static void shut_fd( Display *dpy, int i ) { if (dpy->fd[i].fd < 0) return; shutdown (dpy->fd[i].fd, SHUT_RDWR); close (dpy->fd[i].fd); dpy->fd[i].fd = -1; dpy->fd[i].readbuf_count = 0; dpy->fd[i].writebuf_count = 0; if (i == 0) { fprintf(stderr, "server connection lost\n"); exit(1); } else { /* Pass this to the application as a DestroyNotify event. */ XEvent *er = queue_event(dpy); if (!er) return; er->xdestroywindow.type = DestroyNotify; er->xdestroywindow.serial = 0; er->xdestroywindow.send_event = 0; er->xdestroywindow.display = dpy; er->xdestroywindow.window = (Window)i; } } /** * \brief Send a message to a socket connection. * * \param dpy the display handle. * \param i the index in dpy->fd of the socket connection. * \param msg the message to send. * \param sz the size of the message * * \internal * Copy the message to the write buffer for the nominated connection. * This will be actually sent to that file descriptor from * __miniglx_Select(). */ int send_msg( Display *dpy, int i, const void *msg, size_t sz ) { int cnt = dpy->fd[i].writebuf_count; if (MINIGLX_BUF_SIZE - cnt < sz) { fprintf(stderr, "client %d: writebuf overflow\n", i); return False; } memcpy( dpy->fd[i].writebuf + cnt, msg, sz ); cnt += sz; dpy->fd[i].writebuf_count = cnt; return True; } /** * \brief Send a message to a socket connection. * * \param dpy the display handle. * \param i the index in dpy->fd of the socket connection. * \param msg the message to send. * * \internal * Use send_msg() to send a one-byte message to a socket. */ int send_char_msg( Display *dpy, int i, char msg ) { return send_msg( dpy, i, &msg, sizeof(char)); } /** * \brief Block and receive a message from a socket connection. * * \param dpy the display handle. * \param connection the index in dpy->fd of the socket connection. * \param msg storage for the received message. * \param msg_size the number of bytes to read. * * \internal * Block and read from the connection's file descriptor * until msg_size bytes have been received. * * Only called from welcome_message_part(). */ int blocking_read( Display *dpy, int connection, char *msg, size_t msg_size ) { int i, r; for (i = 0 ; i < msg_size ; i += r) { r = read(dpy->fd[connection].fd, msg + i, msg_size - i); if (r < 1) { fprintf(stderr, "blocking_read: %d %s\n", r, strerror(errno)); shut_fd(dpy,connection); return False; } } return True; } /** * \brief Send/receive a part of the welcome message. * * \param dpy the display handle. * \param i the index in dpy->fd of the socket connection. * \param msg storage for the sent/received message. * \param sz the number of bytes to write/read. * * \return True on success, or False on failure. * * This function is called by welcome_message_part(), to either send or receive * (via blocking_read()) part of the welcome message, according to whether * Display::IsClient is set. * * Each part of the welcome message on the wire consists of a count and then the * actual message data with that number of bytes. */ static int welcome_message_part( Display *dpy, int i, void **msg, int sz ) { if (dpy->IsClient) { int sz; if (!blocking_read( dpy, i, (char *)&sz, sizeof(sz))) return False; if (!*msg) *msg = malloc(sz); if (!*msg) return False; if (!blocking_read( dpy, i, *msg, sz )) return False; return sz; } else { if (!send_msg( dpy, i, &sz, sizeof(sz))) return False; if (!send_msg( dpy, i, *msg, sz )) return False; } return True; } /** * \brief Send/receive the welcome message. * * \param dpy the display handle. * \param i the index in dpy->fd of the socket connection. * * \return True on success, or False on failure. * * Using welcome_message_part(), sends/receives the client ID, the client * configuration details in DRIDriverContext::shared, and the driver private * message in DRIDriverContext::driverClientMsg. */ static int welcome_message( Display *dpy, int i ) { void *tmp = &dpy->driverContext.shared; int *clientid = dpy->IsClient ? &dpy->clientID : &i; int size; if (!welcome_message_part( dpy, i, (void **)&clientid, sizeof(*clientid))) return False; if (!welcome_message_part( dpy, i, &tmp, sizeof(dpy->driverContext.shared))) return False; size=welcome_message_part( dpy, i, (void **)&dpy->driverContext.driverClientMsg, dpy->driverContext.driverClientMsgSize ); if (!size) return False; if (dpy->IsClient) { dpy->driverContext.driverClientMsgSize = size; } return True; } /** * \brief Handle a new client connection. * * \param dpy the display handle. * * \return True on success or False on failure. * * Accepts the connection, sets it in non-blocking operation, and finds a free * slot in Display::fd for it. */ static int handle_new_client( Display *dpy ) { struct sockaddr_un client_address; unsigned int l = sizeof(client_address); int r, i; r = accept(dpy->fd[0].fd, (struct sockaddr *) &client_address, &l); if (r < 0) { perror ("accept()"); shut_fd(dpy,0); return False; } if (fcntl(r, F_SETFL, O_NONBLOCK) != 0) { perror("fcntl"); close(r); return False; } /* Some rough & ready adaption of the XEvent semantics. */ for (i = 1 ; i < dpy->nrFds ; i++) { if (dpy->fd[i].fd < 0) { XEvent *er = queue_event(dpy); if (!er) { close(r); return False; } dpy->fd[i].fd = r; er->xcreatewindow.type = CreateNotify; er->xcreatewindow.serial = 0; er->xcreatewindow.send_event = 0; er->xcreatewindow.display = dpy; er->xcreatewindow.window = (Window)i; /* fd slot == window, now? */ /* Send the driver client message - this is expected as the * first message on a new connection. The recpient already * knows the size of the message. */ welcome_message( dpy, i ); return True; } } fprintf(stderr, "[miniglx] %s: Max nr clients exceeded\n", __FUNCTION__); close(r); return False; } /** * This routine "puffs out" the very basic communications between * client and server to full-sized X Events that can be handled by the * application. * * \param dpy the display handle. * \param i the index in dpy->fd of the socket connection. * * \return True on success or False on failure. * * \internal * Interprets the message (see msg) into a XEvent and advances the file FIFO * buffer. */ static int handle_fifo_read( Display *dpy, int i ) { drm_magic_t magic; int err; while (dpy->fd[i].readbuf_count) { char id = dpy->fd[i].readbuf[0]; XEvent *er; int count = 1; if (dpy->IsClient) { switch (id) { /* The server has called XMapWindow on a client window */ case _YouveGotFocus: er = queue_event(dpy); if (!er) return False; er->xmap.type = MapNotify; er->xmap.serial = 0; er->xmap.send_event = False; er->xmap.display = dpy; er->xmap.event = dpy->TheWindow; er->xmap.window = dpy->TheWindow; er->xmap.override_redirect = False; if (dpy->driver->notifyFocus) dpy->driver->notifyFocus( 1 ); break; /* The server has called XMapWindow on a client window */ case _RepaintPlease: er = queue_event(dpy); if (!er) return False; er->xexpose.type = Expose; er->xexpose.serial = 0; er->xexpose.send_event = False; er->xexpose.display = dpy; er->xexpose.window = dpy->TheWindow; if (dpy->rotateMode) { er->xexpose.x = dpy->TheWindow->y; er->xexpose.y = dpy->TheWindow->x; er->xexpose.width = dpy->TheWindow->h; er->xexpose.height = dpy->TheWindow->w; } else { er->xexpose.x = dpy->TheWindow->x; er->xexpose.y = dpy->TheWindow->y; er->xexpose.width = dpy->TheWindow->w; er->xexpose.height = dpy->TheWindow->h; } er->xexpose.count = 0; break; /* The server has called 'XUnmapWindow' on a client * window. */ case _YouveLostFocus: er = queue_event(dpy); if (!er) return False; er->xunmap.type = UnmapNotify; er->xunmap.serial = 0; er->xunmap.send_event = False; er->xunmap.display = dpy; er->xunmap.event = dpy->TheWindow; er->xunmap.window = dpy->TheWindow; er->xunmap.from_configure = False; if (dpy->driver->notifyFocus) dpy->driver->notifyFocus( 0 ); break; case _Authorize: dpy->authorized = True; break; default: fprintf(stderr, "Client received unhandled message type %d\n", id); shut_fd(dpy, i); /* Actually shuts down the client */ return False; } } else { switch (id) { /* Lets the server know that the client is ready to render * (having called 'XMapWindow' locally). */ case _CanIHaveFocus: er = queue_event(dpy); if (!er) return False; er->xmaprequest.type = MapRequest; er->xmaprequest.serial = 0; er->xmaprequest.send_event = False; er->xmaprequest.display = dpy; er->xmaprequest.parent = 0; er->xmaprequest.window = (Window)i; break; /* Both _YouveLostFocus and _IDontWantFocus generate unmap * events. The idea is that _YouveLostFocus lets the client * know that it has had focus revoked by the server, whereas * _IDontWantFocus lets the server know that the client has * unmapped its own window. */ case _IDontWantFocus: er = queue_event(dpy); if (!er) return False; er->xunmap.type = UnmapNotify; er->xunmap.serial = 0; er->xunmap.send_event = False; er->xunmap.display = dpy; er->xunmap.event = (Window)i; er->xunmap.window = (Window)i; er->xunmap.from_configure = False; break; case _Authorize: /* is full message here yet? */ if (dpy->fd[i].readbuf_count < count + sizeof(magic)) { count = 0; break; } memcpy(&magic, dpy->fd[i].readbuf + count, sizeof(magic)); fprintf(stderr, "Authorize - magic %d\n", magic); err = drmAuthMagic(dpy->driverContext.drmFD, magic); count += sizeof(magic); send_char_msg( dpy, i, _Authorize ); break; default: fprintf(stderr, "Server received unhandled message type %d\n", id); shut_fd(dpy, i); /* Generates DestroyNotify event */ return False; } } dpy->fd[i].readbuf_count -= count; if (dpy->fd[i].readbuf_count) { memmove(dpy->fd[i].readbuf, dpy->fd[i].readbuf + count, dpy->fd[i].readbuf_count); } } return True; } /** * Handle a VT signal * * \param dpy display handle. * * The VT switches is detected by comparing Display::haveVT and * Display::hwActive. When loosing the VT the hardware lock is acquired, the * hardware is shutdown via a call to DRIDriverRec::shutdownHardware(), and the * VT released. When acquiring the VT back the hardware state is restored via a * call to DRIDriverRec::restoreHardware() and the hardware lock released. */ static void __driHandleVtSignals( Display *dpy ) { dpy->vtSignalFlag = 0; fprintf(stderr, "%s: haveVT %d hwActive %d\n", __FUNCTION__, dpy->haveVT, dpy->hwActive); if (!dpy->haveVT && dpy->hwActive) { /* Need to get lock and shutdown hardware */ DRM_LIGHT_LOCK( dpy->driverContext.drmFD, dpy->driverContext.pSAREA, dpy->driverContext.serverContext ); dpy->driver->shutdownHardware( &dpy->driverContext ); /* Can now give up control of the VT */ ioctl( dpy->ConsoleFD, VT_RELDISP, 1 ); dpy->hwActive = 0; } else if (dpy->haveVT && !dpy->hwActive) { /* Get VT (wait??) */ ioctl( dpy->ConsoleFD, VT_RELDISP, VT_ACTIVATE ); /* restore HW state, release lock */ dpy->driver->restoreHardware( &dpy->driverContext ); DRM_UNLOCK( dpy->driverContext.drmFD, dpy->driverContext.pSAREA, dpy->driverContext.serverContext ); dpy->hwActive = 1; } } #undef max #define max(x,y) ((x) > (y) ? (x) : (y)) /** * Logic for the select() call. * * \param dpy display handle. * \param n highest fd in any set plus one. * \param rfds fd set to be watched for reading, or NULL to create one. * \param wfds fd set to be watched for writing, or NULL to create one. * \param xfds fd set to be watched for exceptions or error, or NULL to create one. * \param tv timeout value, or NULL for no timeout. * * \return number of file descriptors contained in the sets, or a negative number on failure. * * \note * This all looks pretty complex, but is necessary especially on the * server side to prevent a poorly-behaved client from causing the * server to block in a read or write and hence not service the other * clients. * * \sa * See select_tut in the Linux manual pages for more discussion. * * \internal * Creates and initializes the file descriptor sets by inspecting Display::fd * if these aren't passed in the function call. Calls select() and fulfill the * demands by trying to fill MiniGLXConnection::readbuf and draining * MiniGLXConnection::writebuf. * The server fd[0] is handled specially for new connections, by calling * handle_new_client(). * */ int __miniglx_Select( Display *dpy, int n, fd_set *rfds, fd_set *wfds, fd_set *xfds, struct timeval *tv ) { int i; int retval; fd_set my_rfds, my_wfds; struct timeval my_tv; if (!rfds) { rfds = &my_rfds; FD_ZERO(rfds); } if (!wfds) { wfds = &my_wfds; FD_ZERO(wfds); } /* Don't block if there are events queued. Review this if the * flush in XMapWindow is changed to blocking. (Test case: * miniglxtest). */ if (dpy->eventqueue.head != dpy->eventqueue.tail) { my_tv.tv_sec = my_tv.tv_usec = 0; tv = &my_tv; } for (i = 0 ; i < dpy->nrFds; i++) { if (dpy->fd[i].fd < 0) continue; if (dpy->fd[i].writebuf_count) FD_SET(dpy->fd[i].fd, wfds); if (dpy->fd[i].readbuf_count < MINIGLX_BUF_SIZE) FD_SET(dpy->fd[i].fd, rfds); n = max(n, dpy->fd[i].fd + 1); } if (dpy->vtSignalFlag) __driHandleVtSignals( dpy ); retval = select( n, rfds, wfds, xfds, tv ); if (dpy->vtSignalFlag) { int tmp = errno; __driHandleVtSignals( dpy ); errno = tmp; } if (retval < 0) { FD_ZERO(rfds); FD_ZERO(wfds); return retval; } /* Handle server fd[0] specially on the server - accept new client * connections. */ if (!dpy->IsClient) { if (FD_ISSET(dpy->fd[0].fd, rfds)) { FD_CLR(dpy->fd[0].fd, rfds); handle_new_client( dpy ); } } /* Otherwise, try and fill readbuffer and drain writebuffer: */ for (i = 0 ; i < dpy->nrFds ; i++) { if (dpy->fd[i].fd < 0) continue; /* If there aren't any event slots left, don't examine * any more file events. This will prevent lost events. */ if (dpy->eventqueue.head == ((dpy->eventqueue.tail + 1) & MINIGLX_EVENT_QUEUE_MASK)) { fprintf(stderr, "leaving event loop as event queue is full\n"); return retval; } if (FD_ISSET(dpy->fd[i].fd, wfds)) { int r = write(dpy->fd[i].fd, dpy->fd[i].writebuf, dpy->fd[i].writebuf_count); if (r < 1) shut_fd(dpy,i); else { dpy->fd[i].writebuf_count -= r; if (dpy->fd[i].writebuf_count) { memmove(dpy->fd[i].writebuf, dpy->fd[i].writebuf + r, dpy->fd[i].writebuf_count); } } } if (FD_ISSET(dpy->fd[i].fd, rfds)) { int r = read(dpy->fd[i].fd, dpy->fd[i].readbuf + dpy->fd[i].readbuf_count, MINIGLX_BUF_SIZE - dpy->fd[i].readbuf_count); if (r < 1) shut_fd(dpy,i); else { dpy->fd[i].readbuf_count += r; handle_fifo_read( dpy, i ); } } } return retval; } /** * \brief Handle socket events. * * \param dpy the display handle. * \param nonblock whether to return immediately or wait for an event. * * \return True on success, False on failure. Aborts on critical error. * * \internal * This function is the select() main loop. */ int handle_fd_events( Display *dpy, int nonblock ) { while (1) { struct timeval tv = {0, 0}; int r = __miniglx_Select( dpy, 0, 0, 0, 0, nonblock ? &tv : 0 ); if (r >= 0) return True; if (errno == EINTR || errno == EAGAIN) continue; perror ("select()"); exit (1); } } /** * Initializes the connections. * * \param dpy the display handle. * * \return True on success or False on failure. * * Allocates and initializes the Display::fd array and create a Unix socket on * the first entry. For a server binds the socket to a filename and listen for * connections. For a client connects to the server and waits for a welcome * message. Sets the socket in nonblocking mode. */ int __miniglx_open_connections( Display *dpy ) { struct sockaddr_un sa; int i; dpy->nrFds = dpy->IsClient ? 1 : MINIGLX_MAX_SERVER_FDS; dpy->fd = calloc(1, dpy->nrFds * sizeof(struct MiniGLXConnection)); if (!dpy->fd) return False; for (i = 0 ; i < dpy->nrFds ; i++) dpy->fd[i].fd = -1; if (!dpy->IsClient) { if (unlink(MINIGLX_FIFO_NAME) != 0 && errno != ENOENT) { perror("unlink " MINIGLX_FIFO_NAME); return False; } } /* Create a Unix socket -- Note this is *not* a network connection! */ dpy->fd[0].fd = socket(PF_UNIX, SOCK_STREAM, 0); if (dpy->fd[0].fd < 0) { perror("socket " MINIGLX_FIFO_NAME); return False; } memset(&sa, 0, sizeof(sa)); sa.sun_family = AF_UNIX; strcpy(sa.sun_path, MINIGLX_FIFO_NAME); if (dpy->IsClient) { /* Connect to server */ if (connect(dpy->fd[0].fd, (struct sockaddr *)&sa, sizeof(sa)) != 0) { perror("connect"); shut_fd(dpy,0); return False; } /* Wait for configuration messages from the server. */ welcome_message( dpy, 0 ); } else { mode_t tmp = umask( 0000 ); /* open to everybody ? */ /* Bind socket to our filename */ if (bind(dpy->fd[0].fd, (struct sockaddr *)&sa, sizeof(sa)) != 0) { perror("bind"); shut_fd(dpy,0); return False; } umask( tmp ); /* Listen for connections */ if (listen(dpy->fd[0].fd, 5) != 0) { perror("listen"); shut_fd(dpy,0); return False; } } if (fcntl(dpy->fd[0].fd, F_SETFL, O_NONBLOCK) != 0) { perror("fcntl"); shut_fd(dpy,0); return False; } return True; } /** * Frees the connections initialized by __miniglx_open_connections(). * * \param dpy the display handle. */ void __miniglx_close_connections( Display *dpy ) { int i; for (i = 0 ; i < dpy->nrFds ; i++) { if (dpy->fd[i].fd >= 0) { shutdown (dpy->fd[i].fd, SHUT_RDWR); close (dpy->fd[i].fd); } } dpy->nrFds = 0; free(dpy->fd); } /** * Set a drawable flag. * * \param dpy the display handle. * \param w drawable (window). * \param flag flag. * * Sets the specified drawable flag in the SAREA and increment its stamp while * holding the light hardware lock. */ static void set_drawable_flag( Display *dpy, int w, int flag ) { if (dpy->driverContext.pSAREA) { if (dpy->hwActive) DRM_LIGHT_LOCK( dpy->driverContext.drmFD, dpy->driverContext.pSAREA, dpy->driverContext.serverContext ); dpy->driverContext.pSAREA->drawableTable[w].stamp++; dpy->driverContext.pSAREA->drawableTable[w].flags = flag; if (dpy->hwActive) DRM_UNLOCK( dpy->driverContext.drmFD, dpy->driverContext.pSAREA, dpy->driverContext.serverContext ); } } /** * \brief Map Window. * * \param dpy the display handle as returned by XOpenDisplay(). * \param w the window handle. * * If called by a client, sends a request for focus to the server. If * called by the server, will generate a MapNotify and Expose event at * the client. * */ void XMapWindow( Display *dpy, Window w ) { if (dpy->IsClient) send_char_msg( dpy, 0, _CanIHaveFocus ); else { set_drawable_flag( dpy, (int)w, 1 ); send_char_msg( dpy, (int)w, _YouveGotFocus ); send_char_msg( dpy, (int)w, _RepaintPlease ); dpy->TheWindow = w; } handle_fd_events( dpy, 0 ); /* flush write queue */ } /** * \brief Unmap Window. * * \param dpy the display handle as returned by XOpenDisplay(). * \param w the window handle. * * Called from the client: Lets the server know that the window won't * be updated anymore. * * Called from the server: Tells the specified client that it no longer * holds the focus. */ void XUnmapWindow( Display *dpy, Window w ) { if (dpy->IsClient) { send_char_msg( dpy, 0, _IDontWantFocus ); } else { dpy->TheWindow = 0; set_drawable_flag( dpy, (int)w, 0 ); send_char_msg( dpy, (int)w, _YouveLostFocus ); } handle_fd_events( dpy, 0 ); /* flush write queue */ } /** * \brief Block and wait for next X event. * * \param dpy the display handle as returned by XOpenDisplay(). * \param event_return a pointer to an XEvent structure for the returned data. * * Wait until there is a new XEvent pending. */ int XNextEvent(Display *dpy, XEvent *event_return) { for (;;) { if ( dpy->eventqueue.head != dpy->eventqueue.tail ) return dequeue_event( dpy, event_return ); handle_fd_events( dpy, 0 ); } } /** * \brief Non-blocking check for next X event. * * \param dpy the display handle as returned by XOpenDisplay(). * \param event_mask ignored. * \param event_return a pointer to an XEvent structure for the returned data. * * Check if there is a new XEvent pending. Note that event_mask is * ignored and any pending event will be returned. */ Bool XCheckMaskEvent(Display *dpy, long event_mask, XEvent *event_return) { if ( dpy->eventqueue.head != dpy->eventqueue.tail ) return dequeue_event( dpy, event_return ); handle_fd_events( dpy, 1 ); return dequeue_event( dpy, event_return ); }