Re: BUG (non-kernel), can hurt developers.

From: Tomas Szepe
Date: Fri Nov 28 2003 - 02:21:04 EST


On Nov-26 2003, Wed, 10:29 -0800
Linus Torvalds <torvalds@xxxxxxxx> wrote:

> You can't just randomly use library functions in signal handlers. You can
> only use a very specific "signal-safe" set.
>
> POSIX lists that set in 3.3.1.3 (3f), and says
>
> "All POSIX.1 functions not in the preceding table and all
> functions defined in the C standard {2} not stated to be callable
> from a signal-catching function are considered to be /unsafe/
> with respect to signals. .."
>
> typos mine.
>
> The thing is, they have internal state that makes then non-reentrant (and
> note that even the re-entrant ones might not be signal-safe, since they
> may have deadlock issues: being thread-safe is _not_ the same as being
> signal-safe).

I believe it would be very useful to have this information included in
the standard Linux signal(2) manpage. (I've just verified it's not in
man-pages-1.60.)

What do you think, Andries?

--
Tomas Szepe <szepe@xxxxxxxxxxxxxxx>
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