FFI: Problem with Signal Handler Interruptions

[Levi Greenspan]

Apologies for re-posting this subject here since I had sent already a
message to haskell-café 3 days ago, but I just learned about this
mailing list and it seems more appropriate to ask this question here I
guess. I already got a reply from Simon Marlow but I posted some
further (so far unanswered) questions. The thread starts here:
http://www.haskell.org//pipermail/haskell-cafe/2009-August/064880.html.
Basically my remaining questions are:

1.  How can one safely perform a blocking wait on a system call via
FFI when compiling with -threaded and avoid signal interruptions which
cause the call to return with EINTR?
2.  Could 1. be achieved by blocking SIGVTALRM in the thread doing the call?

For details please cf. the original maling list thread.

Many thanks,
Levi