我正在用 C 语言编写我的第一个 X11 应用程序,但在尝试检索应用程序窗口的大小时遇到了一个重大问题。
temp.c:30:2 warning: passing argument 3 of 'XGetGeometry' makes pointer from integer without a cast
我知道这只是一个警告,但它仍然会导致不好玩的段错误。这是我的代码:
static void loop();
static void initialize();
static void cleanUp();
static void run();
/* Variables */
static int screenNumber;
unsigned long White;
unsigned long Black;
long eventMask;
static Display *currentDisplay;
static Window currentWindow;
static unsigned int windowWidth;
static unsigned int windowHeight;
static GC graphicsController;
static XEvent XEvents;
void loop() {
XGetGeometry(currentDisplay, currentWindow, DefaultRootWindow(currentDisplay), NULL, NULL, &windowWidth, &windowHeight, NULL, NULL);
XDrawLine(currentDisplay, currentWindow, graphicsController, 0, 0, (int)windowWidth, (int)windowHeight);
XDrawLine(currentDisplay, currentWindow, graphicsController, 0, (int)windowHeight, (int)windowWidth, 0);
}
void initialize() {
currentDisplay = XOpenDisplay(NULL);
screenNumber = DefaultScreen(currentDisplay);
White = WhitePixel(currentDisplay, screenNumber);
Black = BlackPixel(currentDisplay, screenNumber);
currentWindow = XCreateSimpleWindow( currentDisplay,
DefaultRootWindow(currentDisplay),
0, 0,
500, 500,
0, Black,
White);
XMapWindow(currentDisplay, currentWindow);
XStoreName(currentDisplay, currentWindow, "rGot - X11");
eventMask = StructureNotifyMask;
XSelectInput(currentDisplay, currentWindow, eventMask);
do{
XNextEvent(currentDisplay, &XEvents);
}while(XEvents.type != MapNotify);
graphicsController = XCreateGC(currentDisplay, currentWindow, 0, NULL);
XSetForeground(currentDisplay, graphicsController, Black);
}
void run() {
eventMask = ButtonPressMask|ButtonReleaseMask;
XSelectInput(currentDisplay, currentWindow, eventMask);
do{
XNextEvent(currentDisplay, &XEvents);
loop();
}while(1==1);
}
void cleanUp() {
XDestroyWindow(currentDisplay, currentWindow);
XCloseDisplay(currentDisplay);
}
int main(){
initialize();
run();
cleanUp();
return 0;
}
我知道我的指针做错了,但我对此很陌生......这是我的设置:
- Ubuntu 12.04 LTS
- 编译:
gcc tempc -o temp -lX11
对于那些后来发现这一点的人——我最初的尝试XGetGeometry
是完全错误的!
要正确使用它,我必须执行以下操作:
XGetGeometry(currentDisplay, currentWindow, ¤tRoot, &windowOffsetX, &windowOffsetY, &windowWidth, &windowHeight, &windowBorderWidth, &windowDepth);
这是基于我在这里的发现。