diff options
Diffstat (limited to 'm4/ldexp.m4')
| -rw-r--r-- | m4/ldexp.m4 | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/m4/ldexp.m4 b/m4/ldexp.m4 new file mode 100644 index 0000000..3ad7d0c --- /dev/null +++ b/m4/ldexp.m4 @@ -0,0 +1,54 @@ +# ldexp.m4 serial 1 +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_LDEXP], +[ + AC_REQUIRE([gl_CHECK_LDEXP_NO_LIBM]) + LDEXP_LIBM= + if test $gl_cv_func_ldexp_no_libm = no; then + AC_CACHE_CHECK([whether ldexp() can be used with libm], + [gl_cv_func_ldexp_in_libm], + [ + save_LIBS="$LIBS" + LIBS="$LIBS -lm" + AC_LINK_IFELSE( + [AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES + # define __NO_MATH_INLINES 1 /* for glibc */ + #endif + #include <math.h> + double (*funcptr) (double, int) = ldexp; + double x;]], + [[return ldexp (x, -1) > 0;]])], + [gl_cv_func_ldexp_in_libm=yes], + [gl_cv_func_ldexp_in_libm=no]) + LIBS="$save_LIBS" + ]) + if test $gl_cv_func_ldexp_in_libm = yes; then + LDEXP_LIBM=-lm + fi + fi + AC_SUBST([LDEXP_LIBM]) +]) + +dnl Test whether ldexp() can be used without linking with libm. +dnl Set gl_cv_func_ldexp_no_libm to 'yes' or 'no' accordingly. +AC_DEFUN([gl_CHECK_LDEXP_NO_LIBM], +[ + AC_CACHE_CHECK([whether ldexp() can be used without linking with libm], + [gl_cv_func_ldexp_no_libm], + [ + AC_LINK_IFELSE( + [AC_LANG_PROGRAM([[#ifndef __NO_MATH_INLINES + # define __NO_MATH_INLINES 1 /* for glibc */ + #endif + #include <math.h> + double (*funcptr) (double, int) = ldexp; + double x;]], + [[return ldexp (x, -1) > 0;]])], + [gl_cv_func_ldexp_no_libm=yes], + [gl_cv_func_ldexp_no_libm=no]) + ]) +]) |