1 // 2 // handler_alloc_hook.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com) 6 // 7 // Distributed under the Boost Software License, Version 1.0. (See accompanying 8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 9 // 10 11 #ifndef BOOST_ASIO_HANDLER_ALLOC_HOOK_HPP 12 #define BOOST_ASIO_HANDLER_ALLOC_HOOK_HPP 13 14 #if defined(_MSC_VER) && (_MSC_VER >= 1200) 15 # pragma once 16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) 17 18 #include <boost/asio/detail/config.hpp> 19 #include <cstddef> 20 21 #include <boost/asio/detail/push_options.hpp> 22 23 namespace boost { 24 namespace asio { 25 26 #if defined(BOOST_ASIO_NO_DEPRECATED) 27 28 // Places in asio that would have previously called the allocate or deallocate 29 // hooks to manage memory, now call them only to check whether the result types 30 // are these types. If the result is not the correct type, it indicates that 31 // the user code still has the old hooks in place, and if so we want to trigger 32 // a compile error. 33 enum asio_handler_allocate_is_no_longer_used {}; 34 enum asio_handler_deallocate_is_no_longer_used {}; 35 36 typedef asio_handler_allocate_is_no_longer_used 37 asio_handler_allocate_is_deprecated; 38 typedef asio_handler_deallocate_is_no_longer_used 39 asio_handler_deallocate_is_deprecated; 40 41 #else // defined(BOOST_ASIO_NO_DEPRECATED) 42 43 typedef void* asio_handler_allocate_is_deprecated; 44 typedef void asio_handler_deallocate_is_deprecated; 45 46 #endif // defined(BOOST_ASIO_NO_DEPRECATED) 47 48 /// (Deprecated: Use the associated_allocator trait.) Default allocation 49 /// function for handlers. 50 /** 51 * Asynchronous operations may need to allocate temporary objects. Since 52 * asynchronous operations have a handler function object, these temporary 53 * objects can be said to be associated with the handler. 54 * 55 * Implement asio_handler_allocate and asio_handler_deallocate for your own 56 * handlers to provide custom allocation for these temporary objects. 57 * 58 * The default implementation of these allocation hooks uses <tt>::operator 59 * new</tt> and <tt>::operator delete</tt>. 60 * 61 * @note All temporary objects associated with a handler will be deallocated 62 * before the upcall to the handler is performed. This allows the same memory to 63 * be reused for a subsequent asynchronous operation initiated by the handler. 64 * 65 * @par Example 66 * @code 67 * class my_handler; 68 * 69 * void* asio_handler_allocate(std::size_t size, my_handler* context) 70 * { 71 * return ::operator new(size); 72 * } 73 * 74 * void asio_handler_deallocate(void* pointer, std::size_t size, 75 * my_handler* context) 76 * { 77 * ::operator delete(pointer); 78 * } 79 * @endcode 80 */ 81 BOOST_ASIO_DECL asio_handler_allocate_is_deprecated 82 asio_handler_allocate(std::size_t size, ...); 83 84 /// Default deallocation function for handlers. 85 /** 86 * Implement asio_handler_allocate and asio_handler_deallocate for your own 87 * handlers to provide custom allocation for the associated temporary objects. 88 * 89 * The default implementation of these allocation hooks uses <tt>::operator 90 * new</tt> and <tt>::operator delete</tt>. 91 * 92 * @sa asio_handler_allocate. 93 */ 94 BOOST_ASIO_DECL asio_handler_deallocate_is_deprecated 95 asio_handler_deallocate(void* pointer, std::size_t size, ...); 96 97 } // namespace asio 98 } // namespace boost 99 100 #include <boost/asio/detail/pop_options.hpp> 101 102 #if defined(BOOST_ASIO_HEADER_ONLY) 103 # include <boost/asio/impl/handler_alloc_hook.ipp> 104 #endif // defined(BOOST_ASIO_HEADER_ONLY) 105 106 #endif // BOOST_ASIO_HANDLER_ALLOC_HOOK_HPP 107