Macro: ac_cxx_partial_ordering

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# ac_cxx_partial_ordering

## Synopsis

`AC_CXX_PARTIAL_ORDERING`

## Version

1.1.1.1 (2001/07/26) C++_Support @ ac-archive-0.5.32

## Author

Luc Maisonobe

## Description

If the compiler supports partial ordering, define HAVE_PARTIAL_ORDERING.

## M4 Source Code

    AC_DEFUN([AC_CXX_PARTIAL_ORDERING],
    [AC_CACHE_CHECK(whether the compiler supports partial ordering,
    ac_cv_cxx_partial_ordering,
    [AC_LANG_SAVE
     AC_LANG_CPLUSPLUS
     AC_TRY_COMPILE([
    template<int N> struct I {};
    template<class T> struct A
    {  int r;
       template<class T1, class T2> int operator() (T1, T2)       { r = 0; return r; }
       template<int N1, int N2>     int operator() (I<N1>, I<N2>) { r = 1; return r; }
    };],[A<float> x, y; I<0> a; I<1> b; return x (a,b) + y (float(), double());],
     ac_cv_cxx_partial_ordering=yes, ac_cv_cxx_partial_ordering=no)
     AC_LANG_RESTORE
    ])
    if test "$ac_cv_cxx_partial_ordering" = yes; then
      AC_DEFINE(HAVE_PARTIAL_ORDERING,,
                [define if the compiler supports partial ordering])
    fi
    ])