AC_DEFUN([AC_CXX_COMPLEX_MATH_IN_NAMESPACE_STD],
[AC_CACHE_CHECK(whether complex math functions are in std::,
ac_cv_cxx_complex_math_in_namespace_std,
[AC_REQUIRE([AC_CXX_NAMESPACES])
AC_LANG_SAVE
AC_LANG_CPLUSPLUS
AC_TRY_COMPILE([#include <complex>
namespace S { using namespace std;
complex<float> pow(complex<float> x, complex<float> y)
{ return std::pow(x,y); }
};
],[using namespace S; complex<float> x = 1.0, y = 1.0; S::pow(x,y); return 0;],
ac_cv_cxx_complex_math_in_namespace_std=yes, ac_cv_cxx_complex_math_in_namespace_std=no)
AC_LANG_RESTORE
])
if test "$ac_cv_cxx_complex_math_in_namespace_std" = yes; then
AC_DEFINE(HAVE_COMPLEX_MATH_IN_NAMESPACE_STD,,
[define if complex math functions are in std::])
fi
])