On 27.03.2008, at 21:59, Harvey Chapman wrote:
Why does ...
#define MT(name) { name::Type, name::Create }
work, and ...
#define MT(name) { name##::Type, name##::Create }
does not?
Is that first one portable? I understand the error I get for the
second one about name and :: not constituting a valid pre-processor
token, but the first one seems wrong to me. Is :: used in a macro a
special case? Or is it an operator? Just looking for some insight to
help me remember this.
AFAIK :: is a delimiter to the preprocessor (similar to ,). Hence,
the first one should be portable; the latter one does not work as the
result of the concatenation has to be a token.
To clarify this in the code , you could even write:
#define MT(name) { name :: Type, name :: Create }
(Well, just a guess -- I am *never* sure when it comes to the
preprocessor....)
Daniel
