[qmtest] [PATCH] Use processes instead of threads

[Nathaniel Smith]

On Wed, Apr 28, 2004 at 11:36:21PM -0700, Zack Weinberg wrote:
> I am not particularly concerned about this either, but it does seem
> more abstractly correct to me to record the signal mask at startup
> (before creating any threads) and restore that after fork.
> 
> I might be inclined to patch the Python core to do this, using
> pthread_atfork, except that wouldn't help us.

Amusingly, the signal module defines a function called
"PyOS_AfterFork", which appears to be responsible for resetting
various thread stuffs after a fork.  It just doesn't touch signals at
all (which makes it location all the curiouser).  I don't really
understand the Python source; PyOS_AfterFork is also defined in
Parser/intrcheck.c, somehow, with a somewhat different API.

In any case, this function should probably be doing signal mask stuff.

This still wouldn't fix the problem entirely, because popen(),
system() etc. don't trigger a call to PyOS_AfterFork (quoth
Doc/api/utilities.tex, "If a new executable is loaded into the new
process, this function does not need to be called"), so pthread_atfork
would perhaps be a better course.

Except, as you say, none of this would help us, not being able to
require users to use a fixed version of Python :-).

-- Nathaniel

-- 
"But suppose I am not willing to claim that.  For in fact pianos
are heavy, and very few persons can carry a piano all by themselves."