1# ceil.m4 serial 15
2dnl Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7AC_DEFUN([gl_FUNC_CEIL],
8[
9  m4_divert_text([DEFAULTS], [gl_ceil_required=plain])
10  AC_REQUIRE([gl_MATH_H_DEFAULTS])
11  dnl Test whether ceil() can be used without libm.
12  gl_FUNC_CEIL_LIBS
13  if test "$CEIL_LIBM" = "?"; then
14    CEIL_LIBM=
15  fi
16  m4_ifdef([gl_FUNC_CEIL_IEEE], [
17    if test $gl_ceil_required = ieee && test $REPLACE_CEIL = 0; then
18      AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
19      AC_CACHE_CHECK([whether ceil works according to ISO C 99 with IEC 60559],
20        [gl_cv_func_ceil_ieee],
21        [
22          save_LIBS="$LIBS"
23          LIBS="$LIBS $CEIL_LIBM"
24          AC_RUN_IFELSE(
25            [AC_LANG_SOURCE([[
26#ifndef __NO_MATH_INLINES
27# define __NO_MATH_INLINES 1 /* for glibc */
28#endif
29#include <math.h>
30]gl_DOUBLE_MINUS_ZERO_CODE[
31]gl_DOUBLE_SIGNBIT_CODE[
32static double dummy (double f) { return 0; }
33int main (int argc, char *argv[])
34{
35  double (* volatile my_ceil) (double) = argc ? ceil : dummy;
36  int result = 0;
37  /* Test whether ceil (-0.0) is -0.0.  */
38  if (signbitd (minus_zerod) && !signbitd (my_ceil (minus_zerod)))
39    result |= 1;
40  /* Test whether ceil (-0.3) is -0.0.  */
41  if (signbitd (-0.3) && !signbitd (my_ceil (-0.3)))
42    result |= 2;
43  return result;
44}
45            ]])],
46            [gl_cv_func_ceil_ieee=yes],
47            [gl_cv_func_ceil_ieee=no],
48            [case "$host_os" in
49                              # Guess yes on glibc systems.
50               *-gnu* | gnu*) gl_cv_func_ceil_ieee="guessing yes" ;;
51                              # Guess yes on musl systems.
52               *-musl*)       gl_cv_func_ceil_ieee="guessing yes" ;;
53                              # Guess yes on native Windows.
54               mingw*)        gl_cv_func_ceil_ieee="guessing yes" ;;
55                              # If we don't know, obey --enable-cross-guesses.
56               *)             gl_cv_func_ceil_ieee="$gl_cross_guess_normal" ;;
57             esac
58            ])
59          LIBS="$save_LIBS"
60        ])
61      case "$gl_cv_func_ceil_ieee" in
62        *yes) ;;
63        *) REPLACE_CEIL=1 ;;
64      esac
65    fi
66  ])
67  if test $REPLACE_CEIL = 1; then
68    dnl No libraries are needed to link lib/ceil.c.
69    CEIL_LIBM=
70  fi
71  AC_SUBST([CEIL_LIBM])
72])
73
74# Determines the libraries needed to get the ceil() function.
75# Sets CEIL_LIBM.
76AC_DEFUN([gl_FUNC_CEIL_LIBS],
77[
78  gl_CACHE_VAL_SILENT([gl_cv_func_ceil_libm], [
79    gl_cv_func_ceil_libm=?
80    AC_LINK_IFELSE(
81      [AC_LANG_PROGRAM(
82         [[#ifndef __NO_MATH_INLINES
83           # define __NO_MATH_INLINES 1 /* for glibc */
84           #endif
85           #include <math.h>
86           double (*funcptr) (double) = ceil;
87           double x;]],
88         [[x = funcptr(x) + ceil(x);]])],
89      [gl_cv_func_ceil_libm=])
90    if test "$gl_cv_func_ceil_libm" = "?"; then
91      save_LIBS="$LIBS"
92      LIBS="$LIBS -lm"
93      AC_LINK_IFELSE(
94        [AC_LANG_PROGRAM(
95           [[#ifndef __NO_MATH_INLINES
96             # define __NO_MATH_INLINES 1 /* for glibc */
97             #endif
98             #include <math.h>
99             double (*funcptr) (double) = ceil;
100             double x;]],
101           [[x = funcptr(x) + ceil(x);]])],
102        [gl_cv_func_ceil_libm="-lm"])
103      LIBS="$save_LIBS"
104    fi
105  ])
106  CEIL_LIBM="$gl_cv_func_ceil_libm"
107])
108