# =========================================================================== # https://www.gnu.org/software/autoconf-archive/ax_c_arithmetic_rshift.html # =========================================================================== # # SYNOPSIS # # AX_C_ARITHMETIC_RSHIFT # # DESCRIPTION # # Checks if the right shift operation is arithmetic. # # This macro uses compile-time detection and so is cross-compile ready. # # LICENSE # # Copyright (c) 2008 YAMAMOTO Kengo # # Copying and distribution of this file, with or without modification, are # permitted in any medium without royalty provided the copyright notice # and this notice are preserved. This file is offered as-is, without any # warranty. #serial 10 AC_DEFUN([AX_C_ARITHMETIC_RSHIFT], [ AC_CACHE_CHECK([whether right shift operation is arithmetic], [ax_cv_c_arithmetic_rshift], [AC_COMPILE_IFELSE([AC_LANG_SOURCE([[int dummy[((-1 >> 1) < 0) ? 1 : -1];]])], [ax_cv_c_arithmetic_rshift=yes], [ax_cv_c_arithmetic_rshift=no])]) if test "x$ax_cv_c_arithmetic_rshift" = xyes; then AC_DEFINE([HAVE_ARITHMETIC_RSHIFT], [1], [Define to 1 if the right shift operation is arithmetic.]) fi ])