Thread: Problem with macros and templates

I'm trying to get two VS2008 projects (of which neither are written by me) that separately compiles just fine, to work together.

When I include a header from the first project in the second, I get this error:

Code:

 ... Defs.hpp(195) : warning C4002: too many actual parameters for macro 'min'

Here is the code that generates the error

Code:

#define FW_CUDA_FUNC     __device__ __inline__

#define FW_SPECIALIZE_MINMAX(TEMPLATE, T, MINVAL, MAXVAL) \
    TEMPLATE FW_CUDA_FUNC T min(T a, T b) { return MINVAL; } \
    TEMPLATE FW_CUDA_FUNC T max(T a, T b) { return MAXVAL; } \
    TEMPLATE FW_CUDA_FUNC T min(T a, T b, T c) { return min(min(a, b), c); } \
    TEMPLATE FW_CUDA_FUNC T max(T a, T b, T c) { return max(max(a, b), c); } \
    TEMPLATE FW_CUDA_FUNC T min(T a, T b, T c, T d) { return min(min(min(a, b), c), d); } \
    TEMPLATE FW_CUDA_FUNC T max(T a, T b, T c, T d) { return max(max(max(a, b), c), d); } \
    TEMPLATE FW_CUDA_FUNC T min(T a, T b, T c, T d, T e) { return min(min(min(min(a, b), c), d), e); } \
    TEMPLATE FW_CUDA_FUNC T max(T a, T b, T c, T d, T e) { return max(max(max(max(a, b), c), d), e); } \
    TEMPLATE FW_CUDA_FUNC T min(T a, T b, T c, T d, T e, T f) { return min(min(min(min(min(a, b), c), d), e), f); } \
    TEMPLATE FW_CUDA_FUNC T max(T a, T b, T c, T d, T e, T f) { return max(max(max(max(max(a, b), c), d), e), f); } \
    TEMPLATE FW_CUDA_FUNC T min(T a, T b, T c, T d, T e, T f, T g) { return min(min(min(min(min(min(a, b), c), d), e), f), g); } \
    TEMPLATE FW_CUDA_FUNC T max(T a, T b, T c, T d, T e, T f, T g) { return max(max(max(max(max(max(a, b), c), d), e), f), g); } \
    TEMPLATE FW_CUDA_FUNC T min(T a, T b, T c, T d, T e, T f, T g, T h) { return min(min(min(min(min(min(min(a, b), c), d), e), f), g), h); } \
    TEMPLATE FW_CUDA_FUNC T max(T a, T b, T c, T d, T e, T f, T g, T h) { return max(max(max(max(max(max(max(a, b), c), d), e), f), g), h); } \
    TEMPLATE FW_CUDA_FUNC T clamp(T v, T lo, T hi) { return min(max(v, lo), hi); }


FW_SPECIALIZE_MINMAX(template <class T>, T&, (a < b) ? a : b, (a > b) ? a : b)

Row 195 is the last row in the code above.

As both project compile separately, I'm thinking this has something to do with (pre?)compiler options. I've tried to isolate the error by looking at differences in settings between the two projects, but I don't really know where to look.

Any ideas would be greatly appreciated!

Make them template functions instead of macros.

Template functions were my suggestion because that looks like what the poster wants to use. I don't need to sell my advice and I don't want anyone doing it for me.

Originally Posted by King Mir

That's not what it looks like; I'd expect a different error message, if one at all. Creating a min function in the global namespace should not conflict with namespace std. Now it could be a non conforming standard library implementation.

As a quick fix, you could write #undef min above the code you posted. However, this may have other side effects.

Thanks! The #undef min and #undef max fixed it.

You could also define NOMINMAX before including windows.h, because that's always the problem when there's shenanigans with min or max identifiers.

this problem could much more easily be solved by declaring the functions like so:

Code:

template<typename T>
T getMin(std::initializer_list<T> theList);

template<typename T>
T getMax(std::initializer_list<T> theList);

then you would call them like so:

Code:

int theMax = getMax({1, 3, 5, 7, 9, 0});
double theMin = getMin({1.0, 3.0, 5.0, 7.0, 9.0, 0.0});