dir.c:525
static VALUE
dir_s_mkdir(argc, argv, obj)
    int argc;
    VALUE *argv;
    VALUE obj;
{
    VALUE path, vmode;
    int mode;

    if (rb_scan_args(argc, argv, "11", &path, &vmode) == 2) {
	mode = NUM2INT(vmode);
    }
    else {
	mode = 0777;
    }

    SafeStringValue(path);
    rb_secure(2);
#ifndef _WIN32
    if (mkdir(RSTRING(path)->ptr, mode) == -1)
	rb_sys_fail(RSTRING(path)->ptr);
#else
    if (mkdir(RSTRING(path)->ptr) == -1)
	rb_sys_fail(RSTRING(path)->ptr);
#endif

    return INT2FIX(0);
}
