warnings in msvc about mix/max macro while windows.h is used in the project

[crea7or]

In the version 2.1.1, msvc generates a few warnings about std::numeric_limits<>::max() (and min) usage. This is because windows.h have their own min/max macros definitions in the global namespace (here is microsoft kb article about it..
warning exact text: warning C4003: not enough actual parameters for macro 'max'

possible fixes:
1)

#define NOMINMAX

#ifdef max
#undef max
#endif

#ifdef min
#undef min
#endif

3. use additional parenthesis

std::numeric_limits<uint8_t>::max() => (std::numeric_limits<uint8_t>::max)()

First two methods can produce problems, due to use original windows min/max in the gdi and more.
the third method should be tested on the other compilers.

Source to reproduce the problem:

#include "stdafx.h"
#include "windows.h"
#include "json.hpp"

using json = nlohmann::json;

int main( int argc, char const *argv[] )
{
	json j;
	j[ "test" ] = 1;
}

[nlohmann]

Does this also occur in the develop branch?

[crea7or]

just tested dev branch - yes, even the errors appeared:

json.hpp(3583): warning C4003: not enough actual parameters for macro 'min'
json.hpp(3583): error C2589: '(': illegal token on right side of '::'
json.hpp(3583): error C2062: type 'unknown-type' unexpected
json.hpp(3583): error C2059: syntax error: ')'
json.hpp(3513): error C3615: constexpr function 'nlohmann::detail::operator ==' cannot result in a constant expression
json.hpp(3513): note: failure was because type 'nlohmann::detail::primitive_iterator_t' is not a literal type
...

changing line 3583 from:
difference_type m_it = std::numeric_limits<std::ptrdiff_t>::min();
to
difference_type m_it = (std::numeric_limits<std::ptrdiff_t>::min)();
fixes all the problems.

[nlohmann]

Thanks! I'll have a look.

[nlohmann]

@crea7or Can you please check if this works now?

[crea7or]

Everything is clear in visual studio 2015 + visual studio 2017 with all available sdk versions:

[nlohmann]

Thanks for checking!