How to make sure that signal handlers are run?

[Igor Khavkine <i_khavki@alcor.concordia.ca>]

Hi, I'm communicating with the libgc upstream author to integrate
Hurd support into the library. I got the latest snapshot of the
source to compile, but it's failing one of the tests during
`make check'.

I think the problem is somehow related to registered signal handlers
not being run properly. I have made sure that the proper signal
handlers are set but monitoring calls to sigaction() from GDB. I have
inserted printf() (and even write()) statements into the possible
signal handlers. I've also marked them with break points from GDB.
However, neither of the break points occurred during execution. Nor
was there any output on the screen from the printf() statments
that I have insterted.

So how can I make sure that the proper signal handlers are called when
necessary? Or at least, how can I find out which signal handlers were
actually called?

Thanks.

Igor