What was the signal?

[Guy Harris]

>I have a C program doing a msgrcv(2) which may be interrupted by a SIGALRM. This
>is processed by a handler function. On return a failure of msgrcv is found
>and found to be due to an interrupt. The question is, will any ignored signal
>(ignored by default) also interrupt the msgrcv,

I assume by "ignored by default" you mean that the action for the signal
is SIG_DFL, rather than SIG_IGN, but that the default action for the
signal is to do nothing.  If so, then an ignored signal will interrupt
the "msgrcv()" only if you have a Mutant UNIX From Hell; the same
applies to explicitly-ignored signals.