Mercurial > gnulib
view m4/ffs.m4 @ 40215:88b18d82fa61
crypto/des: Fix undefined behaviour.
* lib/des.c (READ_64BIT_DATA): Cast bytes to 'unsigned int', to avoid
shift operations on 'int'.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Sat, 09 Mar 2019 22:21:25 +0100 |
parents | b06060465f09 |
children |
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# ffs.m4 serial 4 dnl Copyright (C) 2011-2019 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_FFS], [ AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS]) dnl We can't use AC_CHECK_FUNC here, because ffs() is defined as a dnl static inline function when compiling for Android 4.2 or older. dnl But require that ffs() is declared; otherwise we may be using dnl the GCC built-in function, which leads to warnings dnl "warning: implicit declaration of function 'ffs'". AC_CACHE_CHECK([for ffs], [gl_cv_func_ffs], [AC_LINK_IFELSE( [AC_LANG_PROGRAM( [[#include <strings.h> int x; ]], [[int (*func) (int) = ffs; return func (x); ]]) ], [gl_cv_func_ffs=yes], [gl_cv_func_ffs=no]) ]) if test $gl_cv_func_ffs = no; then HAVE_FFS=0 fi ])