Created attachment 17531 [details]
test case source C code

Hello!


This simple test case hangs on Linux (ubuntu 8.04) where libX11 uses xcb 1.1 library. On Linux where libX11 uses non-xcb libraries program run ok that means
it should print:

XInitThreads  1
>x=0,y=0
>x=0,y=0
>x=0,y=0
>x=0,y=0
>x=0,y=0
<x=0,y=0
<x=0,y=0
<x=0,y=0
<x=0,y=0
<x=0,y=0


It creates 5 threads and run fun() function for each thread. And never occurs
28 line of t.c test case:
  printf("<x=%d,y=%d\n",dest_x_return,dest_y_return);

where use xcb only prints:

XInitThreads  1
>x=0,y=0
>x=0,y=0
>x=0,y=0
>x=0,y=0
>x=0,y=0

and hang.

Problem consider Ubuntu 8.04 LTS (i386). Ubuntu 7.10 is not affected because libX11 not use XCB.


it was compiled via:
$  gcc -lX11 -lpthread t.c 

gcc 4.2.3