Nasm and GCC

[regedit]

I am just wanting to combine a Nasm obj with C obj to create an .exe

But the only compile options I run across are for kernels not aps..

Does any one here know what options are needed?

Nasm -f obj file.asm
GCC ???
how would I link with into a gcc linked exe
Under XP -

nasm

Code: Select all

[BITS 32]
_Some_function:

ret

gcc

Code: Select all

int main()
{
    Some_function();
}

[Troy Martin]

I really don't know, I'm not good at C with OS development, but I think you might need an extern somewhere.

Sorry I can't help much,
Troy

[stephenj]

I've never tried this in Windows before, but this link appears useful.

[regedit]

Thanks : stephenj
It worked!

also no extern was needed.. :Troy Martin
but thanks anyway!

you just need to define the funtion in the c app like below:
nasm:
_function:

ret

gcc:
void function();
int main()
{
funtion();
return 0;
}

[Khaoticmind]

For what i know it might have worked, but the correct way to deal with it is with an extern.
When you do

Code: Select all

void function();
int main()
{
funtion();
return 0;
}

You are telling the compiler that function() will be defined later in the same translation unit (the way C calls a file, so to say). What, obviously is not the case.
This might have worked with ld (what gcc calls to link everything), but is not guaranteed to work in other compilers.

You should do

Code: Select all

extern void function();
int main()
{
funtion();
return 0;
}

To say that function() is in a extern translation unit (file). And then everything should be ok

Cheers,
KM

[Ztane]

This might have worked with ld (what gcc calls to link everything), but is not guaranteed to work in other compilers.

Actually, extern with function declaration should be no-op, see http://c-faq.com/decl/extern.html.

[Khaoticmind]

This might have worked with ld (what gcc calls to link everything), but is not guaranteed to work in other compilers.

Actually, extern with function declaration should be no-op, see http://c-faq.com/decl/extern.html.

Good point! Otherwise no linking would ever work with my code
My mistake!