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# ldexp.m4 serial 1 |
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dnl Copyright (C) 2010-2023 Free Software Foundation, Inc. |
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dnl This file is free software; the Free Software Foundation |
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dnl gives unlimited permission to copy and/or distribute it, |
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dnl with or without modifications, as long as this notice is preserved. |
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AC_DEFUN([gl_FUNC_LDEXP], |
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[ |
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AC_REQUIRE([gl_CHECK_LDEXP_NO_LIBM]) |
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LDEXP_LIBM= |
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if test $gl_cv_func_ldexp_no_libm = no; then |
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AC_CACHE_CHECK([whether ldexp() can be used with libm], |
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[gl_cv_func_ldexp_in_libm], |
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[ |
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save_LIBS="$LIBS" |
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LIBS="$LIBS -lm" |
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AC_LINK_IFELSE( |
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[AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES |
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# define __NO_MATH_INLINES 1 |
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#endif |
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#include <math.h> |
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double (*funcptr) (double, int) = ldexp; |
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double x;]], |
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[[return ldexp (x, -1) > 0;]])], |
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[gl_cv_func_ldexp_in_libm=yes], |
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[gl_cv_func_ldexp_in_libm=no]) |
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LIBS="$save_LIBS" |
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]) |
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if test $gl_cv_func_ldexp_in_libm = yes; then |
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LDEXP_LIBM=-lm |
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fi |
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fi |
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AC_SUBST([LDEXP_LIBM]) |
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]) |
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dnl Test whether ldexp() can be used without linking with libm. |
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dnl Set gl_cv_func_ldexp_no_libm to 'yes' or 'no' accordingly. |
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AC_DEFUN([gl_CHECK_LDEXP_NO_LIBM], |
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[ |
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AC_CACHE_CHECK([whether ldexp() can be used without linking with libm], |
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[gl_cv_func_ldexp_no_libm], |
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[ |
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AC_LINK_IFELSE( |
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[AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES |
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# define __NO_MATH_INLINES 1 |
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#endif |
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#include <math.h> |
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double (*funcptr) (double, int) = ldexp; |
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double x;]], |
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[[return ldexp (x, -1) > 0;]])], |
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[gl_cv_func_ldexp_no_libm=yes], |
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[gl_cv_func_ldexp_no_libm=no]) |
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]) |
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]) |
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