Re: Unix-daemons in Ada

[Florian Weimer <fw@deneb.enyo.de>]

Stefan Nobis <stefan@snobis.de> writes:

> I'm learning Ada and i tried to write a simple Unix daemon in Ada (a very
> simple web server). I want the main process, which is attached to a tty, to
> exit, something like
> 
> if (fork()) exit 0;
> else do_real_work();
> 
> in C.

Usually, you can't call fork() from Ada and do complicated things in
the child process (besides an execve()).  This has to do with the fact
that most fork() implementations don't duplicate the whole process
(only the current thread of execution), and that the runtime might
have stored PIDs which become outdated after this operation.

So it's best to detach *before* the Ada runtime is initialized.  How
you can achieve this depends on your Ada implementation.