1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 // <optional> 11 12 #include <experimental/optional> 13 14 #ifndef _LIBCPP_VERSION 15 #error _LIBCPP_VERSION not defined 16 #endif 17 main()18int main() 19 { 20 } 21