Re: Explicitly specializing std::min() on VC++ 2005 Express Edition

"Matthias Hofmann" <>
Fri, 4 May 2007 12:59:20 +0200
"Tom Widmer [VC++ MVP]" <> schrieb im Newsbeitrag

Ahh, of course that won't work for arrays of char. For your template
above, you'd need to do this:

template <class T>
struct min_impl
  static const T& impl(const T& a, const T& b)
  { return a < b ? a : b; }

template <class T> inline
const T& minimum( const T& a, const T& b )
{ return min_impl<T>::impl(a, b); }

Then you can specialize min_impl for char arrays:

template <std::size_t N>
struct min_impl<char[N]>;

This specialization for non-const char[N] seems superflous, as minimum<T>()
accepts a constant reference, so min_impl<T>::impl() will never see a
non-const char[N].

template <std::size_t N>
struct min_impl<char const[N]>;

What does the definition of this specialization of min_impl look like? On
VC++ 2005 Express Edition, I get a compile time error with the following

#include <cstring>
#include <iostream>

template <class T> struct minimum_impl
    static const T& minimum(
        const T& a, const T& b )
        return a < b ? a : b;

template <std::size_t N> struct minimum_impl<char[N]>
    // Compile time error for the following line!
    static const char(&)[N] minimum(
        const char a(&)[N], const char b(&)[N] )
        return std::strcmp( a, b ) < 0 ? a : b;

template <class T> inline
const T& minimum( const T& a, const T& b )
    return minimum_impl<T>::minimum( a, b );

int main()
    char a[] = "a";
    char b[] = "b";

    std::cout << minimum( a, b ) << std::endl;

    return 0;

Matthias Hofmann
Anvil-Soft, CEO - The Creators of Toilet Tycoon - Die Macher des Klomanagers

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