Date: Tue, 24 Nov 1998 10:28:56 -0500 From: "Kaleb S. KEITHLEY" <kaleb@ics.com> To: hackers@FreeBSD.ORG Subject: Re: ELF Global Constructors Message-ID: <365AD0B8.E50AC6C3@ics.com> References: <199811240822.TAA07814@cimlogic.com.au>
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John Birrell wrote:
>
> Jonathan Gapen wrote:
> > I'm in the process of porting GNUstep to FreeBSD 3.0, and I've run
> > into a lack of documentation. Consequently, I don't know where the
> > problem lies. It's like this:
> > GNUstep needs to have a function _gnu_process_args() called before
> > main() to set up information about the process for use by the Foundation
> > library. On non-Linux ELF systems, it tries this bit of code:
> >
> > static void *__gnustep_base_subinit_args__
> > __attribute__ ((section ("_libc_subinit"))) = &(_gnu_process_args);
> >
> > This is where the lack of documentation is getting me. I can't find
> > out what *will* work. I don't know if this is the correct way to hook in
> > a function call before main() and FreeBSD is broken, or egcs is broken, or
> > if it's the wrong way entirely.
> > I'm not even sure where to dig into the system source to find out
> > what's going on, so I'd appreciate any help/pointers. Thanks!
>
> For an example of a constructor, have a look at:
>
> src/lib/libc_r/uthread/uthread_autoinit.cc
>
> This is how a threaded process is initialised prior to the process calling
> main(). This code works with the in-tree compiler (I haven't used egcs, so
> I'm not sure about that).
The ELF Specification (a.k.a. the System V ABI) says that the .init()
function in the shared lib(s) is/are called before main().
Likewise the .fini() function is called after the program exits
normally.
Any initialization the shared library needs, e.g. calling global
constructors, can be put there.
--
Kaleb
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