LinuxQuestions.org - Linux - enumerate X window system

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Linux - enumerate X window system - window id

Hello,

I have some problems how to find id of some window in X. I'm lost :\

Can you pick me some books, functions, API's or else how to find window id? The only thing that i want to do is to send a message to some window, but i need to know the id(windows terminology - handle).

Thanks in advance...

EDIT: To describe best the problem, in MS windows for example there are several ways to get window handle... like FindWindow(...). Wait, wait, wait... yea it's MS, don't blame me. Thats why i want to start exploring Linux dev with few simple tasks so any info is most appreciated.

How do you wish to specify the window to identify? To click on it?

If so you can use the xwininfo command. This changes the cursor to a cross hairs, and when you click on a window, the program output something like this:

Code:

xwininfo: Window id: 0x4000007 "matthew@chubby: ~/bin - Shell - Konsole"



  Absolute upper-left X:  0

  Absolute upper-left Y:  23

  Relative upper-left X:  0

  Relative upper-left Y:  0

  Width: 1680

  Height: 978

  Depth: 24

  Visual Class: TrueColor

  Border width: 0

  Class: InputOutput

  Colormap: 0x20 (installed)

  Bit Gravity State: NorthWestGravity

  Window Gravity State: NorthWestGravity

  Backing Store State: NotUseful

  Save Under State: no

  Map State: IsViewable

  Override Redirect State: no

  Corners:  +0+23  -0+23  -0-49  +0-49

  -geometry 1680x978+0+0

You could post-process this and extract the window id:

Code:

xwininfo |grep 'Window id:' |cut -d" " -f4

Really thanks, but is there a way to do it in C/C++ ? Currently im trying to debug panels like XFCE panel and etc. to find out how is it implented there... u know when u click on the title of some window and the window is popping up. So that means it should send to the window id _NET_ACTIVE_WINDOW...

I think i found the answer and it is XQueryTree. Thanks again matthewg42. I saw the source of xwininfo and it helped me quite much. Also with this tool you can check if you are on the right way ;)