我试图用Xlib来控制Xterm.
为此,我正在制作一个带有奇怪标题的Xterm.在我列出所有窗口并检查它们的名称之后.但有些东西被窃听,我的Xterm的名字在列出时没有出现.这是列出所有窗口的代码:
void CMD::getWindowTerminal()
{
Atom a = XInternAtom(m_display, "_NET_CLIENT_LIST", true);
Atom actualType;
int format;
unsigned long numItems, bytesAfter;
unsigned char *data = 0;
int status = XGetWindowProperty(m_display, m_root_win, a, 0L, (~0L), false,
AnyPropertyType, &actualType, &format, &numItems,
&bytesAfter, &data);
if (status >= Success && numItems)
{
long *array = (long*) data;
for (unsigned long k = 0; k < numItems; k++)
{
// get window Id:
Window w = (Window) array[k];
char* name = '\0';
status = XFetchName(m_display, w, &name);
if (status >= Success)
{
std::cout << w << " " << name << std::endl;
if (name == NULL)
{
m_window_terminal = w;
std::cout << "TERMINAL FOUND" << std::endl;
}
}
XFree(name);
}
XFree(data);
}
}
解决方法:
我无法重现错误;你的代码找到我的xterm窗口.你在查询你刚刚产生的xterm的窗口吗?如果是这样,你可能会遇到竞争条件,因为你试图在xterm有机会之前找到窗口.在这种情况下,一个糟糕的解决方案是稍等一会再试几次.
如果不是这种情况,我只能推测(更多)有关原因(我的推测涉及行为不端的窗口管理器或非常旧的软件),但也许我可以建议一个解决方案:如果xterm没有显示在根窗口中_NET_CLIENT_LIST,让我们直接挖掘窗口树,看看我们是否可以在那里找到它.这个C代码(移植到C应该不难,并且无论如何都可以尝试)以XQueryTree递归遍历窗口树,因此它查询所有窗口:
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/keysym.h>
Window window_from_name_search(Display *display, Window current, char const *needle) {
Window retval, root, parent, *children;
unsigned children_count;
char *name = NULL;
/* Check if this window has the name we seek */
if(XFetchName(display, current, &name) > 0) {
int r = strcmp(needle, name);
XFree(name);
if(r == 0) {
return current;
}
}
retval = 0;
/* If it does not: check all subwindows recursively. */
if(0 != XQueryTree(display, current, &root, &parent, &children, &children_count)) {
unsigned i;
for(i = 0; i < children_count; ++i) {
Window win = window_from_name_search(display, children[i], needle);
if(win != 0) {
retval = win;
break;
}
}
XFree(children);
}
return retval;
}
// frontend function: open display connection, start searching from the root window.
Window window_from_name(char const *name) {
Display *display = XOpenDisplay(NULL);
Window w = window_from_name_search(display, XDefaultRootWindow(display), name);
XCloseDisplay(display);
return w;
}
由于它处理所有窗口,因此您的xterm窗口必须在其中.如果不是,请返回开头(关于可能的竞争条件的位).如果那不是它,那么有些事情很奇怪.