Calling other functions while concurrently calling exit?

[Rich Felker]

On Sat, Sep 19, 2015 at 12:10:41PM +0200, Ondřej Bílka wrote:
> On Sat, Sep 19, 2015 at 08:48:21AM +0200, Andreas Schwab wrote:
> > "Carlos O'Donell" <carlos@redhat.com> writes:
> > 
> > > Is it spelled out anywhere in POSIX or ISO C that calling
> > > other functions concurrently with exit is going to result
> > > in undefined behaviour?
> > 
> > exit must be thread-safe, except that calling it more than once is
> > undefined.
> > 
> Wait, we don't do sane thing and first cancel all other threads before doing anything?

You cannot cancel threads that are currently running code that was not
designed to be cancellable. Doing so is extremely dangerous.

> How otherwise we would run tls destructors in context of correct thread?

TLS destructors only run when the thread exit, either by being the one
to call exit or by exiting as a thread (e.g. pthread_exit). This is
all specified.

Rich