ceph/src/boost/libs/dll/example/tutorial9/tutorial9.cpp

   1 // Copyright 2015-2019 Antony Polukhin.
   2 //
   3 // Distributed under the Boost Software License, Version 1.0.
   4 // (See accompanying file LICENSE_1_0.txt
   5 // or copy at http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #include <boost/predef/os.h>
   8 #if BOOST_OS_WINDOWS
   9
  10 //[callplugcpp_tutorial9
  11 #include <boost/dll/import.hpp>         // for dll::import
  12 #include <boost/dll/shared_library.hpp> // for dll::shared_library
  13 #include <boost/function.hpp>
  14 #include <iostream>
  15 #include <windows.h>
  16
  17 namespace dll = boost::dll;
  18
  19 int main() {
  20     typedef HANDLE(__stdcall GetStdHandle_t)(DWORD );       // function signature with calling convention
  21
  22     // OPTION #0, requires C++11 compatible compiler that understands GetStdHandle_t signature.
  23 /*<-*/
  24 #if defined(_MSC_VER) && !defined(BOOST_NO_CXX11_TRAILING_RESULT_TYPES) && !defined(BOOST_NO_CXX11_DECLTYPE) && !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES) && !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) /*->*/
  25     auto get_std_handle = dll::import<GetStdHandle_t>(
  26         "Kernel32.dll",
  27         "GetStdHandle",
  28         boost::dll::load_mode::search_system_folders
  29     );
  30     std::cout << "0.0 GetStdHandle() returned " << get_std_handle(STD_OUTPUT_HANDLE) << std::endl;
  31
  32     // You may put the `get_std_handle` into boost::function<>. But boost::function<Signature> can not compile with
  33     // Signature template parameter that contains calling conventions, so you'll have to remove the calling convention.
  34     boost::function<HANDLE(DWORD)> get_std_handle2 = get_std_handle;
  35     std::cout << "0.1 GetStdHandle() returned " << get_std_handle2(STD_OUTPUT_HANDLE) << std::endl;
  36 /*<-*/
  37 #endif /*->*/
  38
  39     // OPTION #1, does not require C++11. But without C++11 dll::import<> can not handle calling conventions,
  40     // so you'll need to hand write the import.
  41     dll::shared_library lib("Kernel32.dll", dll::load_mode::search_system_folders);
  42     GetStdHandle_t& func = lib.get<GetStdHandle_t>("GetStdHandle");
  43
  44     // Here `func` does not keep a reference to `lib`, you'll have to deal with that on your own.
  45     std::cout << "1.0 GetStdHandle() returned " << func(STD_OUTPUT_HANDLE) << std::endl;
  46
  47     return 0;
  48 }
  49
  50 //]
  51
  52 #else // BOOST_WINDOWS
  53
  54 #include <boost/dll/shared_library.hpp> // for dll::shared_library
  55
  56 int main() {
  57     return 0;
  58 }
  59
  60 #endif // BOOST_WINDOWS