lua-users home
lua-l archive

[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index] [Thread Index]

On Sep 29, 2004, at 12:41, Daniel Walker wrote:

Unfortunately I can't really accept that solution as the
necessity for it is the exact problem I wished to address.
Furthermore, you may notice that

 #ifndef LUA_API
 #ifdef __cplusplus
 #define LUA_API extern "C"
 #define LUA_API extern

is perfectly valid C code, which completely eliminates the
need for any C++ specifics, and would keep the issue in
question from ever arising again. There really isn't any
benefit in not writing a header like this, so why not?

That code is conforming C code, but not strictly conforming C code. Since it uses a pre-processor token ("__cplusplus") that is in the namespace reserved for the implementation, then any given C implementation is allowed to assigned whatever meaning it likes to that code. Only the language C++ assigns a meaning to __cplusplus, the language C makes no guarantees. It is only when you use a cooperating C implementation that __cplusplus will have the meaning you like. In other words a C implementation is at perfect liberty to define the token __cplusplus for its own purposes.

Adding C++ code to the standard Lua distribution would require the maintainers to maintain the C++ code as well. I'm sure they don't want to do that.

The standard way for a C++ program to include a C header file is to go:
extern "C" {
#include "c-header.h"
why is it that C++ programmers seem so squeamish about doing this?

Basically, I approve of the Lua maintainers' current position.

David Jones