[Boost-users] Boost.Preprocessor with __LINE__ in MSVC71

From: Wu Yinghui, Freddie (yhwu_at_[hidden])
Date: 2006-03-08 04:00:02

Hi all,

I'm observing an interesting problem on MSVC71 regarding the use of 
__LINE__ with Boost.Preprocessor.

The code looks like this
==== snip ====
#include <boost/preprocessor/cat.hpp>
#define UNIQUE_ID   BOOST_PP_CAT(id, __LINE__)
#define UNIQUE_ID2   BOOST_PP_CAT(id, _MSC_VER)
int main()
{
     int UNIQUE_ID2 = 321;
     int UNIQUE_ID = 123;
     bool UNIQUE_ID = false;
}
==== snip ====

The compiler works fine with UNIQUE_ID2, but not UNIQUE_ID. The only 
different in them is only the use of __LINE__ instead of _MSC_VER.

Does anyone on the list has more insight on this issue?

Or, what're the common ways to generate an unique identifier 
automatically within certain scope?

Cheers,

Freddie

-- 
Wu Yinghui, Freddie
Research & Development
Software Engineer
Volume Interactions Pte Ltd
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