Re: linking with ld

[Maciej Hrebien <m_hrebien@wp.pl>]

Mateusz Srebrny wrote:
> 
> Hi,
> 
> I have question about ld.
> Precisely:
> I have an ELF object (produced by nasm) defining global procedure named
> start.
> I want to link it with object made by 'gcc -c' on file loking like this:
> 
> #include <stdio.h>
> 
> extern void start(void);
> 
> int main() {
>   start();
>   return 0;
> }
> 
> I tried 'ld main.o start.o -o main -lc'...

You can link it using gcc, not ld directly like this: gcc -o mail
main.o start.o. It should work just fine.

> it complained sth about not defining _start label, and then refused to
> execute main file (which was produced despite ld warnings)...

_start is the default entry point. If You won't create any global label
named _start in Your code then the ld doesn't know what to put in ELF
header as a starting point. You may set it explicitly using ld's -e
option which i think is the good solution if You can't link with gcc
like in above example.
 
> I wanted to do it with ld, 'couse I thought that linker is to link
> things...
> Of course linking it with gcc works, but again I thought that compiler
> is to compile things to objects...

gcc works with ld. gcc sends its results to ld.
 
> and the info for ld doesn't offer help in the matter... (at least I
> don't see it there)
> 
> I would be grateful for your help...
>         Mateusz Srebrny
> 
> PS the question "why do I want to link a nasm object with a C one?" is
> very difficult to answer... i just have to do it...

-- 
Maciej Hrebien