executable?

/*
 *  call-seq:
 *     stat.executable?    => true or false
 *  
 *  Returns <code>true</code> if <i>stat</i> is executable or if the
 *  operating system doesn't distinguish executable files from
 *  nonexecutable files. The tests are made using the effective owner of
 *  the process.
 *     
 *     File.stat("testfile").executable?   #=> false
 *     
 */

static VALUE
rb_stat_x(obj)
    VALUE obj;
{
    struct stat *st = get_stat(obj);

#ifdef USE_GETEUID
    if (geteuid() == 0) {
        return st->st_mode & S_IXUGO ? Qtrue : Qfalse;
    }
#endif
#ifdef S_IXUSR
    if (rb_stat_owned(obj))
        return st->st_mode & S_IXUSR ? Qtrue : Qfalse;
#endif
#ifdef S_IXGRP
    if (rb_stat_grpowned(obj))
        return st->st_mode & S_IXGRP ? Qtrue : Qfalse;
#endif
#ifdef S_IXOTH
    if (!(st->st_mode & S_IXOTH)) return Qfalse;
#endif
    return Qtrue;
}