HP - fork & exec in Threads hang - intermittently

[Ajay Bakhshi]

Hi,

I am facing the following problem on HP.

Background:

I have a GUI (QT package) and I am running tasks in Threads. These threads
spawn a process and read the output of the process and then display the O/P
on the GUI.
Now I can get a new process spawned by using a menu option. 

Now every alternate time the process hangs (spawned from the same gui):

I.e. First process hangs.  
    Second goes through fine.
    Third goes fine
    Fourth hangs.


More on the problem:

This is what happens, when I call 

os.fork()

In the parent process I get the Pid of the child and the parent is fine.
But in the child process (even before calling exec) my print statements work
but anything os.XXX function call fails. I did a very simple stuff: before
calling exec:
Os.system("touch /tmp/m1") and this system call fails (for situations where
the process hangs).


NOTE: The hp system is:

HP-UX 11.11
It has MSCS cluster installed on it.

Python: 2.2.3

Has any body seen such a hanging of processes.

Thanks
-Ajay B









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