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[Caml-list] Binding C libraries which use variable arguments (stdarg.h)
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Date: 2009-11-01 (12:16)
From: Florian Weimer <fw@d...>
Subject: Re: [Caml-list] Binding C libraries which use variable arguments (stdarg.h)
* Adrien:

> On 01/11/2009, Florian Weimer <> wrote:
>> * Adrien:
>>> It turned out it worked on linux x86_32, linux x86_64, netbsd sparc64
>>> with 32-bit userland, debian's kfreebsd amd64 and ppc32. There's
>>> windows which I haven't checked yet though.
>> x86_64 has different calling conventions for varargs and non-varargs
>> functions.  If it works for you, it's only by accident (e.g. because
>> you aren't passing floating-point arguments).
> I tried a few things with "double" at first since I'm on x86_64 and
> got no warning and no problem whatsoever.

Could you check if libffi sets the %rax register to the number of
floating-point arguments?  (I've seen this working by mere chance in
many cases.)