non rentrant functions causing thread safe function crashes.

[Jeremy Linton <jli at greshamstorage dot com>]

Hi,

I've been lurking for a while but I have a specific problem with glibc 
that doesn't occur on other unix's.

In general, is it acceptable behavior for a function marked as non 
reentrant to cause cause side affects in routines that are required to 
be thread safe? In particular, should I be concerned about crashes in 
thread safe library functions if I call a function that isn't required 
to be thread safe in another thread (even once?).

I can't find anything in the standard which implies this, rather I find 
the opposite. The standard makes it clear that every effort should be 
made to get correct behavior in a threaded environment even for routines 
that aren't _required_ to be thread safe. There isn't a single function 
marked as never being thread safe.

Basically, because of this problem I'm concerned that I should _NEVER_ 
use any function marked as non reentrant in a threaded program.