I took over the first perl FFI, C::DynaLib some years ago, when gcc still defaulted to the simple cdecl calling convention. Push args with alloca on the stack, and call the functions without args, but the alloca'ed args were picked up by the called func. Simple and fast.

For some time now cdecl does not work anymore OOTB, and I thought it's the new gcc-4 stack-protector, tls or such which broke the ABI. It was not. It also fails with gcc-3.4 with the same new layout, but at least I understand now the new gcc ABI and found a way to con…