problems with sigset, sighold and sigrelse.

[zaccone at psuvax.UUCP]

In an earlier article, I described some problems that I was having with
sigset, sighold and sigrelse.  Since I wrote that article, I've
discovered that I don't really understand how these routines work.
Therefore, I'm going to restate my problem and ask for more general
help.

I'm trying to write to a device (via 'write') with both TANDEM and RAW
modes set.  I would also like to catch the SIGINT signal, but I don't
want any I/O operation to be interrupted.

Right now, I'm trying something like this:

sigset(SIGINT, fn);

sighold(SIGINT);

some code with writes in it

sigrelse(SIGINT);

Even with this code, some write operation gets interrupted and does not
return normally (# of bytes attempted != # actually written).

Why is this happening?  What am I doing wrong?

Rick Zaccone
Penn State University
{allegra, burdvax}!psuvax!zaccone