using std::isnan; int foo(float f) {return isnan(f);}])
])
+AC_DEFUN([AC_FUNC_ISINF],[
+AC_SINGLE_CXX_CHECK([HAVE_ISINF_IN_MATH_H], [ac_cv_func_isinf_in_math_h],
+ [isinf], [<math.h>],
+ [#include <math.h>
+ int foo(float f) {return isinf(f);}])
+AC_SINGLE_CXX_CHECK([HAVE_ISINF_IN_CMATH], [ac_cv_func_isinf_in_cmath],
+ [isinf], [<cmath>],
+ [#include <cmath>
+ int foo(float f) {return isinf(f);}])
+AC_SINGLE_CXX_CHECK([HAVE_STD_ISINF_IN_CMATH], [ac_cv_func_std_isinf_in_cmath],
+ [std::isinf], [<cmath>],
+ [#include <cmath>
+ using std::isinf; int foo(float f) {return isinf(f);}])
+])