m4/floor.m4

   1 # floor.m4 serial 8
   2 dnl Copyright (C) 2007, 2009-2014 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 $REPLACE_FLOOR = 0; then
  18       AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  19       AC_CACHE_CHECK([whether floor works according to ISO C 99 with IEC 60559],
  20         [gl_cv_func_floor_ieee],
  21         [
  22           save_LIBS="$LIBS"
  23           LIBS="$LIBS $FLOOR_LIBM"
  24           AC_RUN_IFELSE(
  25             [AC_LANG_SOURCE([[
  26 #ifndef __NO_MATH_INLINES
  27 # define __NO_MATH_INLINES 1 /* for glibc */
  28 #endif
  29 #include <math.h>
  30 ]gl_DOUBLE_MINUS_ZERO_CODE[
  31 ]gl_DOUBLE_SIGNBIT_CODE[
  32 static double dummy (double f) { return 0; }
  33 int main (int argc, char *argv[])
  34 {
  35   double (*my_floor) (double) = argc ? floor : dummy;
  36   /* Test whether floor (-0.0) is -0.0.  */
  37   if (signbitd (minus_zerod) && !signbitd (my_floor (minus_zerod)))
  38     return 1;
  39   return 0;
  40 }
  41             ]])],
  42             [gl_cv_func_floor_ieee=yes],
  43             [gl_cv_func_floor_ieee=no],
  44             [case "$host_os" in
  45                        # Guess yes on glibc systems.
  46                *-gnu*) gl_cv_func_floor_ieee="guessing yes" ;;
  47                        # If we don't know, assume the worst.
  48                *)      gl_cv_func_floor_ieee="guessing no" ;;
  49              esac
  50             ])
  51           LIBS="$save_LIBS"
  52         ])
  53       case "$gl_cv_func_floor_ieee" in
  54         *yes) ;;
  55         *) REPLACE_FLOOR=1 ;;
  56       esac
  57     fi
  58   ])
  59   if test $REPLACE_FLOOR = 1; then
  60     dnl No libraries are needed to link lib/floor.c.
  61     FLOOR_LIBM=
  62   fi
  63   AC_SUBST([FLOOR_LIBM])
  64 ])
  65
  66 # Determines the libraries needed to get the floor() function.
  67 # Sets FLOOR_LIBM.
  68 AC_DEFUN([gl_FUNC_FLOOR_LIBS],
  69 [
  70   gl_CACHE_VAL_SILENT([gl_cv_func_floor_libm], [
  71     gl_cv_func_floor_libm=?
  72     AC_LINK_IFELSE(
  73       [AC_LANG_PROGRAM(
  74          [[#ifndef __NO_MATH_INLINES
  75            # define __NO_MATH_INLINES 1 /* for glibc */
  76            #endif
  77            #include <math.h>
  78            double x;]],
  79          [[x = floor(x);]])],
  80       [gl_cv_func_floor_libm=])
  81     if test "$gl_cv_func_floor_libm" = "?"; then
  82       save_LIBS="$LIBS"
  83       LIBS="$LIBS -lm"
  84       AC_LINK_IFELSE(
  85         [AC_LANG_PROGRAM(
  86            [[#ifndef __NO_MATH_INLINES
  87              # define __NO_MATH_INLINES 1 /* for glibc */
  88              #endif
  89              #include <math.h>
  90              double x;]],
  91            [[x = floor(x);]])],
  92         [gl_cv_func_floor_libm="-lm"])
  93       LIBS="$save_LIBS"
  94     fi
  95   ])
  96   FLOOR_LIBM="$gl_cv_func_floor_libm"
  97 ])