X11 binding, XGetWindowProperty, and different behaviour for

[Jason House]

What type is Window? D will pass it differently based on type. Also, did you use the proper extern statement when declaring external API functions?

Simon Gomizelj Wrote:

> On Fri, 03 Apr 2009 04:09:25 -0400, Simon Gomizelj <simongmzlj at gmail.com>  
> wrote:
> 
> > As a personal learning D/learn X11 project, I thought it would be  
> > interesting to try to port dwm over to D. Building it up nice and  
> > slowly, right now I'm trying to collect a list of windows and their  
> > states a-la dwm.c code.
> >
> > The D code, which is translated from C code, does not work, it returns:
> > X Error of failed request:  BadValue (integer parameter out of range for  
> > operation)
> >    Major opcode of failed request:  20 (X_GetProperty)
> >    Value in failed request:  0x2
> >    Serial number of failed request:  29
> >    Current serial number in output stream:  29
> >
> > The C++ code, which is the D code translated back, does work. The code  
> > fails on a call to XGetWindowProperty. Debugging each shows that both  
> > the C++ and D code pass the same atom, display, and window. Setting  
> > WM_STATE_ELEMENTS < 2 causes the D code to start to segfault while the  
> > C++ code still seems to work.
> >
> > The std.c.linux.X11.X and std.c.linux.X11.Xlib modules I grabbed off of  
> > http://www.dsource.org/projects/bindings/browser/trunk/X11?order=date.  
> > The rest are hand translated (but unconsequential, XGetWindowProperty is  
> > contained in Xlib). X.d and Xlib.d look correct enough.
> >
> > I've spent a full day looking at this code, and I can't seem to  
> > determine why the D code fails. Anyone have any ideas? Thanks in advance.
> >
> 
> C++ code:
> long getstate(Window window)
> {
>      static const long WM_STATE_ELEMENTS = 2L;
> 
>      unsigned long nitems;
>      unsigned long leftover;
>      Atom xa_WM_STATE, actual_type;
>      int actual_format;
>      int status;
>      unsigned char* p = NULL;
> 
>      xa_WM_STATE = XInternAtom(display, "WM_STATE", false);
>      cout << "debug: atom " << xa_WM_STATE << endl;
> 
>      cout << "debug: XGetWindowProperty on window " << window << endl;
>      status = XGetWindowProperty(display, window,
>                    xa_WM_STATE, 0L, WM_STATE_ELEMENTS,
>                    false, xa_WM_STATE, &actual_type, &actual_format,
>                    &nitems, &leftover, &p);
> 
>      if(status == 0)
>      {
>          cout << "RETURN:" << ((p != NULL) ? (long)*p : -1) << " leftover:"  
> << leftover << " nitems:" << nitems << endl;
>          XFree(p);
>          return (p != NULL) ? (long)*p : -1;
>      }
>      return -1;
> }
> 
> D code:
> long getstate(Window window)
> {
>      static const long WM_STATE_ELEMENTS = 2L;
> 
>      uint nitems;
>      uint leftover;
>      Atom xa_WM_STATE, actual_type;
>      int actual_format;
>      int status;
> 
>      ubyte* p = null;
>      scope(exit) XFree(p);
> 
>      byte[] name = cast(byte[])"WM_STATE\0";
>      xa_WM_STATE = XInternAtom(display, name.ptr, Bool.False);
>      debug output(color.green, "debug: atom {}", xa_WM_STATE);
> 
>      debug output(color.cyan, "debug: XGetWindowProperty on window {}",  
> window);
>      status = XGetWindowProperty(display, window,
>                    xa_WM_STATE, 0L, WM_STATE_ELEMENTS,
>                    Bool.False, xa_WM_STATE, &actual_type, &actual_format,
>                    &nitems, &leftover, &p);
>      debug output(color.cyan, "debug: XGetWindowProperty, result:{}",  
> status);
> 
>      if(status == 0)
>          return (p != null) ? cast(long)*p : -1;
>      return -1;
> }
> 
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