Re: [Caml-list] ocamlc compiles hello world, ocamlopt not

[r0ller <r0ller@freemail.hu>]

Hi Gerd,

Minix3 is an ELF based system indeed. I asked the guys on the minix3 forum and one of the developers said that neither the default minix toolchain (clang) nor the minix port of gcc prepends leading underscores. However, he had a hint about checking if the ocaml package itself is trying to guess during its build whether leading underscore prepending is done on the host system or not. If so, that guessing might have gone wrong in case of minix3. After googling a bit, I found something indicating that point may be valid, (cited from http://asm.sourceforge.net/howto/conventions.html#AEN647 ):

Some C compilers prepend an underscore before every symbol, while others do not.
Particularly, Linux a.out GCC does such prepending, while Linux ELF GCC does not.
If you need to cope with both behaviors at once, see how existing packages do. For instance, get an old Linux source tree, the Elk, qthreads, or OCaml...

If that's true, I'd need to recompile the ocaml package whilst trying to indicate somehow that the minix3 system does not need leading underscore prepending, right? Do you think this to be a valid assumption? If so, do you happen to know how can I influence the ocaml build in such a way?

Thanks&regards,
r0ller


Gerd Stolpmann <info@gerd-stolpmann.de> írta:
>Am Donnerstag, den 10.01.2013, 15:48 +0100 schrieb r0ller:>
> Hi Gerd,>
> >
> Thanks for the quick answer! Please, find the output of nm attached -for the first try, size limit was exceeded, hopefully now it'll get through as attachment.>
>
Interesting. I guess you use an ELF-based system (Minix-3.2)? If not it>
could be a limitation of a.out.>
>
Another theory: the symbol names coming from assembler sources seem to>
always have a leading underscore, which seems to have been auto-added by>
the assembler. This is a very old convention you don't find on modern OS>
anymore, so it could be that this is the source of the problem. See>
http://stackoverflow.com/questions/2627511/why-do-c-compilers-prepend-underscores-to-external-names,>
but pay attention to the fact that at some day the underscore was>
handled differently, and was used for internal symbols. So what could>
have happened: The assembler still thinks that symbols from the C>
compiler are prefixed with an underscore, but this is in fact not true.>
This would be a problem of the installed compiler toolchain. Maybe you>
do not use the right assembler matching the C compiler?>
>
Gerd>
>
>
>
>
> Thanks&regards,>
> r0ller>
> >
> Gerd Stolpmann <info@gerd-stolpmann.de> írta:>
> >Am Donnerstag, den 10.01.2013, 14:57 +0100 schrieb r0ller@freemail.hu:>
> These errors would mean that stdlib.a and libasmrun.a do not contain the>
> symbols they are supposed to contain.>
> What's the output of>
> >
> nm /usr/local/lib/ocaml/libasmrun.a?>
> You should normally find here the missing symbols the linker is>
> complaining about.>
> >
> Gerd>
> >
> ------------------------------------------------------------>>
> Gerd Stolpmann, Darmstadt, Germany    gerd@gerd-stolpmann.de>>
> Creator of GODI and camlcity.org.>>
> Contact details:        http://www.camlcity.org/contact.html>>
> Company homepage:       http://www.gerd-stolpmann.de>>
> *** Searching for new projects! Need consulting for system>>
> *** programming in Ocaml? Gerd Stolpmann can help you.>>
> ------------------------------------------------------------>>
> >>
> >
> >
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------------------------------------------------------------>
Gerd Stolpmann, Darmstadt, Germany    gerd@gerd-stolpmann.de>
Creator of GODI and camlcity.org.>
Contact details:        http://www.camlcity.org/contact.html>
Company homepage:       http://www.gerd-stolpmann.de>
*** Searching for new projects! Need consulting for system>
*** programming in Ocaml? Gerd Stolpmann can help you.>
------------------------------------------------------------>
>
>
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