config/math.m4

   1 dnl GCC_CHECK_LIBM
   2 dnl
   3 dnl Check whether -lm is available.  This is a pre-requisite for
   4 dnl GCC_CHECK_MATH_FUNC so that it will link with -lm.
   5 AC_DEFUN([GCC_CHECK_LIBM],
   6 [AC_CHECK_LIB([m],[sin])])
   7
   8 dnl GCC_CHECK_MATH_HEADERS
   9 dnl
  10 dnl Check for math.h and complex.h.  This is a pre-requisite for
  11 dnl GCC_CHECK_MATH_FUNC so that it includes the right headers.
  12 dnl (Some systems, such as AIX or OpenVMS may define macro for math
  13 dnl  functions).
  14 AC_DEFUN([GCC_CHECK_MATH_HEADERS],
  15 [AC_CHECK_HEADERS_ONCE(math.h complex.h)])
  16
  17 dnl GCC_CHECK_MATH_FUNC([name])
  18 dnl
  19 dnl Check whether math function NAME is available on the system (by compiling
  20 dnl and linking a C program) and run define HAVE_name on success.
  21 dnl
  22 dnl Note that OpenVMS system insists on including complex.h before math.h
  23 AC_DEFUN([GCC_CHECK_MATH_FUNC],
  24 [
  25   AC_REQUIRE([GCC_CHECK_LIBM])
  26   AC_REQUIRE([GCC_CHECK_MATH_HEADERS])
  27   AC_CACHE_CHECK([for $1], [gcc_cv_math_func_$1],
  28                  [AC_LINK_IFELSE([AC_LANG_SOURCE([
  29 #ifdef HAVE_COMPLEX_H
  30 #include <complex.h>
  31 #endif
  32 #ifdef HAVE_MATH_H
  33 #include <math.h>
  34 #endif
  35
  36 int (*ptr)() = (int (*)())$1;
  37
  38 int
  39 main ()
  40 {
  41   return 0;
  42 }
  43 ])],
  44 [gcc_cv_math_func_$1=yes],
  45 [gcc_cv_math_func_$1=no])])
  46   if test $gcc_cv_math_func_$1 = yes; then
  47     AC_DEFINE_UNQUOTED(AS_TR_CPP(HAVE_$1),[1],
  48                        [Define to 1 if you have the `$1' function.])
  49   fi
  50 ])