Re: unique identifiers for guard macros

[Angel Tsankov]

> Why do you need unique guards? The reason why header guards are used is
> to prevent multiple inclusion of a file so the macros are based on the
> file name.
>
> For example, foo.h would have:
>
> #ifndef FOO_H
> #define FOO_H
>
> #endif
>
> Sorry if this isn't very helpful, but I don't see why you would need
> unique guards.

You needn't be sorry for asking - I just had to be more specific, I guess.
In a large project it is possible to have duplicate file names in different folders (and in different namespaces). This is why it is 
better to have some other way to form the guard.