Why is std::min failing when windows.h is included?

Question

The windows.h header file (or more correctly, windef.h that it includes in turn) has macros for min and max which are interfering.

You should #define NOMINMAX before including it.

No need to define anything, just bypass the macro using this syntax:

(std::min)(a, b); // added parentheses around function name
(std::max)(a, b);

I still have trouble occasionally with the windows headers and project wide define of NOMINMAX doesn't always seem to work. As an alternative to using parentheses, I sometimes make the type explicit like so:

auto k = std::min<int>(3, 4);

This also stops the preprocessor from matching to min and is arguably more readable than the parentheses workaround.

As others mentioned, the errors are due to min/max macros that are defined in windows header(s). There are three ways of disabling them.

1) #define NOMINMAX before including header, this is generally a bad technique of defining macros in order to affect the following headers;

2) define NOMINMAX in compiler command line/IDE. The bad part about this decision is that if you want to ship your sources, you need to warn the users to do the same;

3) simply undefine the macros in your code before they are used

#undef min
#undef max

This is probably the most portable and flexible solution.