$clib_file = ($^O eq "MSWin32") ? "MSVCRT40.DLL" : "-lc";
$clib = DynaLoader::dl_findfile($clib_file);
$strlen = DynaLoader::dl_find_symbol($clib, "strlen");
$n = FFI::call($strlen, "cIp", $my_string);
DynaLoader::dl_free_file($clib);