SIGSTOP and Interrupted System Call

From: Tom Davis (tom_at_tomdavis.NOorg.SPAMuk)
Date: 01/27/05 

Date: Thu, 27 Jan 2005 20:13:47 +0000

Hello all,

I'm trying to write a piece of software that requires an arbitrary process to
be stopped (with SIGSTOP) before it performs some task.

However, I'm having a problem, because one of the processes I'm testing
has a SysV IPC message queue receive call in it that blocks. If this
process is then stopped at this point, the program exits with:
  msgrcv: Interrupted system call

By handling the EINTR error that is thrown, my test program can cope.
However, I can't assume that all programs will be written to handle this
can I?

Can anyone recommend a solution? i.e. is there another way to stop or
pause a process? Is there a way of setting "SA_RESTART" for the SIGSTOP
signal from outside the process (I have root access)?

Any help or suggestions that you could give me would be very much
appreciated.

Thank you in advance.

Regards,

         Tom Davis