1# cbrtl.m4 serial 10
2dnl Copyright (C) 2012-2021 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_CBRTL],
8[
9  m4_divert_text([DEFAULTS], [gl_cbrtl_required=plain])
10  AC_REQUIRE([gl_MATH_H_DEFAULTS])
11  AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
12  AC_REQUIRE([gl_FUNC_CBRT])
13
14  dnl Persuade glibc <math.h> to declare cbrtl().
15  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
16
17  dnl Test whether cbrtl() exists. Assume that cbrtl(), if it exists, is
18  dnl defined in the same library as cbrt().
19  save_LIBS="$LIBS"
20  LIBS="$LIBS $CBRT_LIBM"
21  AC_CHECK_FUNCS([cbrtl])
22  LIBS="$save_LIBS"
23  if test $ac_cv_func_cbrtl = yes; then
24    CBRTL_LIBM="$CBRT_LIBM"
25    dnl Also check whether it's declared.
26    dnl IRIX 6.5 has cbrtl() in libm but doesn't declare it in <math.h>.
27    AC_CHECK_DECL([cbrtl], , [HAVE_DECL_CBRTL=0], [[#include <math.h>]])
28
29    save_LIBS="$LIBS"
30    LIBS="$LIBS $CBRTL_LIBM"
31    gl_FUNC_CBRTL_WORKS
32    LIBS="$save_LIBS"
33    case "$gl_cv_func_cbrtl_works" in
34      *yes) ;;
35      *) REPLACE_CBRTL=1 ;;
36    esac
37
38    m4_ifdef([gl_FUNC_CBRTL_IEEE], [
39      if test $gl_cbrtl_required = ieee && test $REPLACE_CBRTL = 0; then
40        AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
41        AC_CACHE_CHECK([whether cbrtl works according to ISO C 99 with IEC 60559],
42          [gl_cv_func_cbrtl_ieee],
43          [
44            save_LIBS="$LIBS"
45            LIBS="$LIBS $CBRTL_LIBM"
46            AC_RUN_IFELSE(
47              [AC_LANG_SOURCE([[
48#ifndef __NO_MATH_INLINES
49# define __NO_MATH_INLINES 1 /* for glibc */
50#endif
51#include <math.h>
52]gl_LONG_DOUBLE_MINUS_ZERO_CODE[
53]gl_LONG_DOUBLE_SIGNBIT_CODE[
54static long double dummy (long double x) { return 0; }
55int main (int argc, char *argv[])
56{
57  extern
58  #ifdef __cplusplus
59  "C"
60  #endif
61  long double cbrtl (long double);
62  long double (* volatile my_cbrtl) (long double) = argc ? cbrtl : dummy;
63  long double f;
64  /* Test cbrtl(-0.0).
65     This test fails on IRIX 6.5.  */
66  f = my_cbrtl (minus_zerol);
67  if (!(f == 0.0L) || (signbitl (minus_zerol) && !signbitl (f)))
68    return 1;
69  return 0;
70}
71              ]])],
72              [gl_cv_func_cbrtl_ieee=yes],
73              [gl_cv_func_cbrtl_ieee=no],
74              [case "$host_os" in
75                                # Guess yes on glibc systems.
76                 *-gnu* | gnu*) gl_cv_func_cbrtl_ieee="guessing yes" ;;
77                                # Guess yes on musl systems.
78                 *-musl*)       gl_cv_func_cbrtl_ieee="guessing yes" ;;
79                                # Guess yes on native Windows.
80                 mingw*)        gl_cv_func_cbrtl_ieee="guessing yes" ;;
81                                # If we don't know, obey --enable-cross-guesses.
82                 *)             gl_cv_func_cbrtl_ieee="$gl_cross_guess_normal" ;;
83               esac
84              ])
85            LIBS="$save_LIBS"
86          ])
87        case "$gl_cv_func_cbrtl_ieee" in
88          *yes) ;;
89          *) REPLACE_CBRTL=1 ;;
90        esac
91      fi
92    ])
93  else
94    HAVE_CBRTL=0
95    HAVE_DECL_CBRTL=0
96  fi
97  if test $HAVE_CBRTL = 0 || test $REPLACE_CBRTL = 1; then
98    dnl Find libraries needed to link lib/cbrtl.c.
99    if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
100      CBRTL_LIBM="$CBRT_LIBM"
101    else
102      AC_REQUIRE([gl_FUNC_FREXPL])
103      AC_REQUIRE([gl_FUNC_LDEXPL])
104      CBRTL_LIBM=
105      dnl Append $FREXPL_LIBM to CBRTL_LIBM, avoiding gratuitous duplicates.
106      case " $CBRTL_LIBM " in
107        *" $FREXPL_LIBM "*) ;;
108        *) CBRTL_LIBM="$CBRTL_LIBM $FREXPL_LIBM" ;;
109      esac
110      dnl Append $LDEXPL_LIBM to CBRTL_LIBM, avoiding gratuitous duplicates.
111      case " $CBRTL_LIBM " in
112        *" $LDEXPL_LIBM "*) ;;
113        *) CBRTL_LIBM="$CBRTL_LIBM $LDEXPL_LIBM" ;;
114      esac
115    fi
116  fi
117  AC_SUBST([CBRTL_LIBM])
118])
119
120dnl Test whether cbrtl() works.
121dnl On OpenBSD 5.1/SPARC, cbrtl(16.0L) is = 1.2599...
122AC_DEFUN([gl_FUNC_CBRTL_WORKS],
123[
124  AC_REQUIRE([AC_PROG_CC])
125  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
126  AC_CACHE_CHECK([whether cbrtl works], [gl_cv_func_cbrtl_works],
127    [
128      AC_RUN_IFELSE(
129        [AC_LANG_SOURCE([[
130#include <math.h>
131extern
132#ifdef __cplusplus
133"C"
134#endif
135long double cbrtl (long double);
136volatile long double x;
137long double y;
138int main ()
139{
140  x = 16.0L;
141  y = cbrtl (x);
142  if (y < 2.0L)
143    return 1;
144  return 0;
145}
146]])],
147        [gl_cv_func_cbrtl_works=yes],
148        [gl_cv_func_cbrtl_works=no],
149        [case "$host_os" in
150           openbsd*) gl_cv_func_cbrtl_works="guessing no";;
151                     # Guess yes on native Windows.
152           mingw*)   gl_cv_func_cbrtl_works="guessing yes";;
153           *)        gl_cv_func_cbrtl_works="guessing yes";;
154         esac
155        ])
156    ])
157])
158