Multithreaded Apps on Linux

[Davy Durham]

I've tried gdb 5.0 and have now downgraded to 4.18

When I debug my multithreaded app which run on linux, it keeps stopping
(with no message) and I have to "cont" to get it to continue...  Then it
eventually give a message:

    Program received signal SIG32, Real-time event 32.
    0x4013017e in sigsuspend () from /lib/libc.so.6

And then I cannot continue at all....

What's going on here...   5.0 gives the same results.....

Any Info, Thanks,
    Davy