[boost] Re: A question to preprocessor gurus

From: Pavel Vozenilek (pavel_vozenilek_at_[hidden])
Date: 2004-04-21 17:35:44

"Arkadiy Vertleyb" <vertleyb_at_[hidden]> wrote:

[snip __COUNTER__ macro question]

> Actually I don't need to have many things on the same line, but I do want
to
> handle inclusions from several headers...  Maybe it's somehow possible to
> generate a unique number from the header file name?  Or use this #include
> mechanism you mentioned?
>
__FILE__/__LINE__ combination is unique across multile TUs.

But it is AFAIK impossible to translate it into numeric value
(preprocessor sees string as one token)
and const char* cannot be used as template parameter.

Though you can name headers as hdr1.hpp, hdr2.hpp, ...
and extract the unique header number via
   __FILE__[sizeof(__FILE__) - 6]
hack to get its ASCII code.

/Pavel