David Brown wrote:

On Wed, May 05, 2004 at 05:16:06PM +0200, Claudio Trento wrote:

...

my g++ compiler show me this warning:

<< warning: unused variable `int caml__dummy_n' >>

It is part of the construct the headers use to implement the CAMLparam... macros. Strictly it isn't necessary in C++, since you can have declarations in the middle of a block, but then there would be different constructs for C and C++.

That would not be a problem: most header files that must work with both C and C++ do that. For example, one thing that the OCaml include files out to start and end with is

#ifdef __cplusplus extern "C" { #endif

...

#ifdef __cplusplus } /* extern "C" */ #endif

Similar things based on the __cplusplus macro allows to obtain header files that are 100% standard compliant with respect to both C and C++.

BTW, what about having a (void) caml__dummy_##x;

at the end of the CAMLxparam... macros? This does shut up the warning, at least on gcc.

This would do the trick, even though it is a bit of a hack. What do the OCaml developers think? Are they willing to accept patches to solve these problems? Cheers,

Roberto