Problem with numeric_limits

Why this doesn't work?

enum : long {MaxValue = std::numeric_limits<long int>::max()};

I'm getting erro开发者_开发技巧r :Error 1 error C2057: expected constant expression

What isn't constant about it? Limits of long int are known at compile time so what's the problem?

The problem is that although std::numeric_limits<long int>::max() function returns constant value it is called in run-time and you need constant value in compile-time

Probably you can just use LONG_MAX value instead (see climits header)?

As the other have said, you need a constant expression (functions don't qualify). Eventually C++1x will support a wider range of constant expressions, including functions. See n2235 and Bjarne Stroustrup's FAQ entry.

Yes, but a function cannot be executed at compile time. max()