BSDI 4.0, threads and signals.

Thomas Wouters thomas at
Wed Nov 3 23:18:27 CET 1999

I've been busy the last two days trying to track down a weird bug in BSDI
4.0.1 compiled python with threads. The problem is that the test_signal test
hangs. Compiling without thread support makes it work fine. So i whipped out
the old gdb ;)

I've tracked it down to the pause() library call. Apparently, compiling with
threads support yields very different libc code for the pause() call. And
the thread version does react to a delivered signal, the signal handler gets
called, but after that, the pause()-code does not return. It does do
something, but gcc -g for some reason doesn't link against a libc with debug
symbols, so i can't exactly see what :P

However, now i'm sort-of stuck. I could but BSDI support, but i doubt it
would bring much reaction without a test program that shows the bug -- and i
dont know how to make one :) I know the basics of threading and even posix
threads, but not the details. Might i be missing something in the way of
configuring the behaviour of pause() in a threaded enviroment ? And what
need I do to compile a teensy-tiny bit of program with threading ? I tried
the thread #defines from python's config.h et al, but that didn't work.

Anyone with any C-clue thread-wise able to give me some pointers ? It would
be greatly appreciated.

Not that this bug needs fixing for me to use python... So i'm not really in
a hurry or anything ;)

Thomas Wouters <thomas at>

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