From: Alan Chen <alan@...>
Date: 2002-01-05T09:27:28+09:00
Subject: [ruby-talk:30251] Re: cdecl vs stdcall

On Sat, Jan 05, 2002 at 04:37:52AM +0900, Shan-leung Maverick WOO wrote:
> On Sat, 5 Jan 2002, Yukihiro Matsumoto wrote:
> 
> > Could you tell me what stdcall is, and what I should do to switch?
> 
> I quote MS's documentation here:
> 
>   A __stdcall function's arguments are pushed onto the stack from right to
>   left, and the called function pops these arguments from the stack before
>   it returns.
> 
> The catch with stdcall is that you cannot do varargs (at least not the
> straightforward way). For those, you can declare them as cdecl.
> 
> For switching, I can only tell the MS story here. There is a compiler
> switch (/Gz) that says use stdcall by default and then there is some
> (typically small) changes to the source code like:
> 
> process.c:594:    RETSIGTYPE (__cdecl *hfunc)_((int)), (__cdecl
> *qfunc)_((int)), (__cdecl *ifunc)_((int));
> 
> I cannot estimate the work needed to get Ruby (1.6.6) to use stdcall
> correctly. To make it compile, I changed roughly 30 lines of source code
> but that won't be sufficient to make it run. It's actually much more
> effort because of the different stack management and GC issues. (And hence
> I resort to use a stub DLL for now and proposing this for consideration
> for future Ruby major release.)
> 
> -- 
> All the best,
> Maverick Woo

Generally, for cross-platform code, I've seen a macro used where the cdecl/stdcall occurs.  The macro may evaluate to nothing on platforms which don't need to specify between cdecl's and stdcalls.

-- alan