55 lines
1.9 KiB
Plaintext
55 lines
1.9 KiB
Plaintext
# ldexp.m4 serial 1
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dnl Copyright (C) 2010-2021 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="$LIBS -lm"
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AC_LINK_IFELSE(
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[AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES
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# define __NO_MATH_INLINES 1 /* for glibc */
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#endif
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#include <math.h>
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double (*funcptr) (double, int) = ldexp;
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double x;]],
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[[return ldexp (x, -1) > 0;]])],
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[gl_cv_func_ldexp_in_libm=yes],
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[gl_cv_func_ldexp_in_libm=no])
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LIBS="$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 /* for glibc */
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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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