kc3-lang/gnulib/m4/expl.m4

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• Hash : 281b825e
  Author :
  Date : 2018-01-01T00:57:25
  

  maint: Run 'make update-copyright'
  

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• m4/expl.m4

• # expl.m4 serial 11
  dnl Copyright (C) 2010-2018 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
  dnl with or without modifications, as long as this notice is preserved.
  
  AC_DEFUN([gl_FUNC_EXPL],
  [
    AC_REQUIRE([gl_MATH_H_DEFAULTS])
    AC_REQUIRE([gl_LONG_DOUBLE_VS_DOUBLE])
    AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  
    dnl Persuade glibc <math.h> to declare expl().
    AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
  
    EXPL_LIBM=
    AC_CACHE_CHECK([whether expl() can be used without linking with libm],
      [gl_cv_func_expl_no_libm],
      [
        AC_LINK_IFELSE(
          [AC_LANG_PROGRAM(
             [[#ifndef __NO_MATH_INLINES
               # define __NO_MATH_INLINES 1 /* for glibc */
               #endif
               #include <math.h>
               long double (*funcptr) (long double) = expl;
               long double x;]],
             [[return funcptr (x) > 1.5
                      || expl (x) > 1.5;]])],
          [gl_cv_func_expl_no_libm=yes],
          [gl_cv_func_expl_no_libm=no])
      ])
    if test $gl_cv_func_expl_no_libm = no; then
      AC_CACHE_CHECK([whether expl() can be used with libm],
        [gl_cv_func_expl_in_libm],
        [
          save_LIBS="$LIBS"
          LIBS="$LIBS -lm"
          AC_LINK_IFELSE(
            [AC_LANG_PROGRAM(
               [[#ifndef __NO_MATH_INLINES
                 # define __NO_MATH_INLINES 1 /* for glibc */
                 #endif
                 #include <math.h>
                 long double (*funcptr) (long double) = expl;
                 long double x;]],
               [[return funcptr (x) > 1.5
                        || expl (x) > 1.5;]])],
            [gl_cv_func_expl_in_libm=yes],
            [gl_cv_func_expl_in_libm=no])
          LIBS="$save_LIBS"
        ])
      if test $gl_cv_func_expl_in_libm = yes; then
        EXPL_LIBM=-lm
      fi
    fi
    dnl On Haiku 2017 the system's native expl() is just a stub: it returns 0.0
    dnl and prints "__expl not implemented" for all arguments.
    dnl On OpenBSD 5.4 the system's native expl() is buggy:
    dnl it returns 'nan' for small values. Test for this anomaly.
    if test $gl_cv_func_expl_no_libm = yes \
       || test $gl_cv_func_expl_in_libm = yes; then
      AC_CACHE_CHECK([whether expl() breaks with small values],
        [gl_cv_func_expl_buggy],
        [save_LIBS="$LIBS"
         LIBS="$EXPL_LIBM"
         AC_RUN_IFELSE(
           [AC_LANG_PROGRAM(
              [[#include <math.h>]],
              [[volatile long double x1 = -1.0;
                volatile long double x2 = -0.8;
                volatile long double x3 = -0.4;
                return expl(x1) == 0.0 || isnan(expl(x1))
                       || isnan(expl(x2)) || isnan(expl(x3));
              ]])
           ],
           [gl_cv_func_expl_buggy=no], [gl_cv_func_expl_buggy=yes],
           [case $host_os in
              haiku* | openbsd*)
                        gl_cv_func_expl_buggy="guessing yes" ;;
                        # Guess no on native Windows.
              mingw*)   gl_cv_func_expl_buggy="guessing no" ;;
              *)        gl_cv_func_expl_buggy="guessing no" ;;
            esac
           ])
         LIBS="$save_LIBS"
        ])
      case "$gl_cv_func_expl_buggy" in
        *yes)
          gl_cv_func_expl_in_libm=no
          gl_cv_func_expl_no_libm=no ;;
      esac
    fi
    if test $gl_cv_func_expl_no_libm = yes \
       || test $gl_cv_func_expl_in_libm = yes; then
      dnl Also check whether it's declared.
      dnl Mac OS X 10.3 has expl() in libc but doesn't declare it in <math.h>.
      AC_CHECK_DECL([expl], , [HAVE_DECL_EXPL=0], [[#include <math.h>]])
    else
      HAVE_DECL_EXPL=0
      HAVE_EXPL=0
      dnl Find libraries needed to link lib/expl.c.
      if test $HAVE_SAME_LONG_DOUBLE_AS_DOUBLE = 1; then
        AC_REQUIRE([gl_FUNC_EXP])
        EXPL_LIBM="$EXP_LIBM"
      else
        AC_REQUIRE([gl_FUNC_ISNANL])
        AC_REQUIRE([gl_FUNC_ROUNDL])
        AC_REQUIRE([gl_FUNC_LDEXPL])
        EXPL_LIBM=
        dnl Append $ISNANL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
        case " $EXPL_LIBM " in
          *" $ISNANL_LIBM "*) ;;
          *) EXPL_LIBM="$EXPL_LIBM $ISNANL_LIBM" ;;
        esac
        dnl Append $ROUNDL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
        case " $EXPL_LIBM " in
          *" $ROUNDL_LIBM "*) ;;
          *) EXPL_LIBM="$EXPL_LIBM $ROUNDL_LIBM" ;;
        esac
        dnl Append $LDEXPL_LIBM to EXPL_LIBM, avoiding gratuitous duplicates.
        case " $EXPL_LIBM " in
          *" $LDEXPL_LIBM "*) ;;
          *) EXPL_LIBM="$EXPL_LIBM $LDEXPL_LIBM" ;;
        esac
      fi
    fi
    AC_SUBST([EXPL_LIBM])
  ])
  

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