m4/floor.m4

   1 # floor.m4 serial 7
   2 dnl Copyright (C) 2007, 2009-2012 Free Software Foundation, Inc.
   3 dnl This file is free software; the Free Software Foundation
   4 dnl gives unlimited permission to copy and/or distribute it,
   5 dnl with or without modifications, as long as this notice is preserved.
   6
   7 AC_DEFUN([gl_FUNC_FLOOR],
   8 [
   9   m4_divert_text([DEFAULTS], [gl_floor_required=plain])
  10   AC_REQUIRE([gl_MATH_H_DEFAULTS])
  11   dnl Test whether floor() can be used without libm.
  12   gl_FUNC_FLOOR_LIBS
  13   if test "$FLOOR_LIBM" = "?"; then
  14     FLOOR_LIBM=
  15   fi
  16   m4_ifdef([gl_FUNC_FLOOR_IEEE], [
  17     if test $gl_floor_required = ieee && test $REPLACE_FLOOR = 0; then
  18       AC_CACHE_CHECK([whether floor works according to ISO C 99 with IEC 60559],
  19         [gl_cv_func_floor_ieee],
  20         [
  21           save_LIBS="$LIBS"
  22           LIBS="$LIBS $FLOOR_LIBM"
  23           AC_RUN_IFELSE(
  24             [AC_LANG_SOURCE([[
  25 #ifndef __NO_MATH_INLINES
  26 # define __NO_MATH_INLINES 1 /* for glibc */
  27 #endif
  28 #include <math.h>
  29 ]gl_DOUBLE_MINUS_ZERO_CODE[
  30 ]gl_DOUBLE_SIGNBIT_CODE[
  31 static double dummy (double f) { return 0; }
  32 int main (int argc, char *argv[])
  33 {
  34   double (*my_floor) (double) = argc ? floor : dummy;
  35   /* Test whether floor (-0.0) is -0.0.  */
  36   if (signbitd (minus_zerod) && !signbitd (my_floor (minus_zerod)))
  37     return 1;
  38   return 0;
  39 }
  40             ]])],
  41             [gl_cv_func_floor_ieee=yes],
  42             [gl_cv_func_floor_ieee=no],
  43             [gl_cv_func_floor_ieee="guessing no"])
  44           LIBS="$save_LIBS"
  45         ])
  46       case "$gl_cv_func_floor_ieee" in
  47         *yes) ;;
  48         *) REPLACE_FLOOR=1 ;;
  49       esac
  50     fi
  51   ])
  52   if test $REPLACE_FLOOR = 1; then
  53     dnl No libraries are needed to link lib/floor.c.
  54     FLOOR_LIBM=
  55   fi
  56   AC_SUBST([FLOOR_LIBM])
  57 ])
  58
  59 # Determines the libraries needed to get the floor() function.
  60 # Sets FLOOR_LIBM.
  61 AC_DEFUN([gl_FUNC_FLOOR_LIBS],
  62 [
  63   gl_CACHE_VAL_SILENT([gl_cv_func_floor_libm], [
  64     gl_cv_func_floor_libm=?
  65     AC_LINK_IFELSE(
  66       [AC_LANG_PROGRAM(
  67          [[#ifndef __NO_MATH_INLINES
  68            # define __NO_MATH_INLINES 1 /* for glibc */
  69            #endif
  70            #include <math.h>
  71            double x;]],
  72          [[x = floor(x);]])],
  73       [gl_cv_func_floor_libm=])
  74     if test "$gl_cv_func_floor_libm" = "?"; then
  75       save_LIBS="$LIBS"
  76       LIBS="$LIBS -lm"
  77       AC_LINK_IFELSE(
  78         [AC_LANG_PROGRAM(
  79            [[#ifndef __NO_MATH_INLINES
  80              # define __NO_MATH_INLINES 1 /* for glibc */
  81              #endif
  82              #include <math.h>
  83              double x;]],
  84            [[x = floor(x);]])],
  85         [gl_cv_func_floor_libm="-lm"])
  86       LIBS="$save_LIBS"
  87     fi
  88   ])
  89   FLOOR_LIBM="$gl_cv_func_floor_libm"
  90 ])