On Thu, 2009-07-02 at 03:01 +0400, Bulat Ziganshin wrote:
Hello Duncan,
Thursday, July 2, 2009, 2:57:29 AM, you wrote:
You don't need it to be the same between Windows and Unix, it just has to be standard on each platform, which it is. There are really only two ABIs in common use on x86, the System V ABI and the MS one (which apart from the stdcall calling convention only differs in the bitfield layout iirc).
you mean that on windows gcc, msvc and all other C compilers use the same ABI for passing and packing structs?
When using the gcc option -mms-bitfields then yes, gcc and msvc use the same ABI for packing structs. As the name suggests, the only difference otherwise is that MSVC uses a non-standard layout for bitfields, but since it's the de-facto native compiler it kind of defines the native C ABI. So as it happens this isn't relevant for the FFI because it does not support bitfields. Duncan