如何戒烟的xlib的XNextEvent例行的阻塞 [英] how to quit the blocking of xlib's XNextEvent

问题描述

在Windows下，图形用户界面线程通常所说的GetMessage等待消息，
当另一个线程中使用PoseMessage把一个消息到队列中，那么
GUI线程将返回的GetMessage（退出阻塞）。

Under windows, the GUI thread usually call GetMessage to waiting for message, when another thread use PoseMessage put a message into the queue, then the GUI thread will return GetMessage (quit blocking).

有谁可以告诉我，当我使用XNextEvent例行Xwindows下，以等待
事件中，我怎么能唤醒的图形用户界面在另一个线程的线程。有一些
像PoseMessage API可以使用吗？

Does anyone can tell me, when I use XNextEvent under XWindows to waiting for event, how can I "wakeup" the GUI thread in another thread. Is there some API like PoseMessage I can use ?.

推荐答案

没有。这就是为什么大多数的UI框架（GTK，KDE等）使用自定义主循环才能够监听多个事件源。

No. This is why most UI frameworks (Gtk, KDE, etc) use custom main loops to be able to listen for more event sources.

在内部，XNextEvent例行使用插座，所以它调用选择（）来知道什么时候输入可用。所以，你能：呼叫 ConnectionNumber（显示）来得到你需要传递的文件描述符选择（）

Internally, XNextEvent uses a socket, so it calls select() to know when input is available. So can you: Call ConnectionNumber(display) to get the file descriptor that you need to pass select()

这可以让你听好文件描述符。

That allows you to listen for several file descriptors.

样$ C $从 HTTP C：//www.linuxquestions。组织/问题/ showthread.php？p = 2431345＃post2431345

#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

Display *dis;
Window win;
int x11_fd;
fd_set in_fds;

struct timeval tv;
XEvent ev;

int main() {
    dis = XOpenDisplay(NULL);
    win = XCreateSimpleWindow(dis, RootWindow(dis, 0), 1, 1, 256, 256, \
        0, BlackPixel (dis, 0), BlackPixel(dis, 0));

    // You don't need all of these. Make the mask as you normally would.
    XSelectInput(dis, win, 
        ExposureMask | KeyPressMask | KeyReleaseMask | PointerMotionMask |
        ButtonPressMask | ButtonReleaseMask  | StructureNotifyMask 
        );

    XMapWindow(dis, win);
    XFlush(dis);

    // This returns the FD of the X11 display (or something like that)
    x11_fd = ConnectionNumber(dis);

    // Main loop
    while(1) {
        // Create a File Description Set containing x11_fd
        FD_ZERO(&in_fds);
        FD_SET(x11_fd, &in_fds);

        // Set our timer.  One second sounds good.
        tv.tv_usec = 0;
        tv.tv_sec = 1;

        // Wait for X Event or a Timer
        int num_ready_fds = select(x11_fd + 1, &in_fds, NULL, NULL, &tv);
        if (num_ready_fds > 0)
            printf("Event Received!\n");
        else if (num_ready_fds == 0)
            // Handle timer here
            printf("Timer Fired!\n");
        else
            printf("An error occured!\n");

        // Handle XEvents and flush the input 
        while(XPending(dis))
            XNextEvent(dis, &ev);
    }
    return(0);
}

这篇关于如何戒烟的xlib的XNextEvent例行的阻塞的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！