Scope of C preprocessor definitions

[arnaudk]

In VC++ 2005, I noticed the scope of any #define's is confined to a single translation unit. In particular, this means that standard inclusion guards of the type
[code=cpp]
#ifndef INCLUDED
#define INCLUDED

[header code...]

#endif
[/code]
would not work. Is there any way to extend the scope of preprocessor definitions beyond a single translation unit and without using compiler switches or unportable #pragmas?

[weaknessforcats]

Of course the inclusion guards woirk over multiple files.

The C/C++ build process is a compile of multiple source files that are then combined into a result by the linker.

The preprocessor operates on one file at a time. The translation unit is passed to the compiler. Done.

The next file needs to have ALL of the #defines required. There is no memory of "the other file". That is, nothing carries over from one file to the next.

It is this structure that allows you to mix C files, C++ files, assembly files, etc in the same build.