XOpenDisplay call sequence

[Krzywicki, Alan]

So if I follow the XOpenDisplay sequence up the stack I see xcb_connect() / _xcb_open_abstract( ) trying to open "/tmp/.X11-unix/X0" with protocol set to 0.   On one system it eventually calls select(), on another it uses poll() instead, so it is looking for a response.  Once in a while it takes over a minute to get a response.   Can anyone describe a general overview of what it is trying to open?  Any idea why the select/poll call hangs so long?

Stack example:

#0  0xffffe424 in __kernel_vsyscall ()
#1  0xb6ad657d in select () from /lib/i686/libc.so.6
#2  0xb68997fc in ?? () from /usr/lib/libxcb.so.1
#3  0xb68985db in xcb_connect_to_fd () from /usr/lib/libxcb.so.1
#4  0xb689b6cd in xcb_connect () from /usr/lib/libxcb.so.1
#5  0xb7004b9b in _XConnectXCB () from /usr/lib/libX11.so.6
#6  0xb6fe5f10 in XOpenDisplay () from /usr/lib/libX11.so.6
#7  0x0805f463 in main ()


/ Alan K.
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