// // async_file_copy.cpp // ~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2024 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #include #include "asio.hpp" #if defined(ASIO_HAS_FILE) class file_copier { public: file_copier(asio::io_context& io_context, const char* from, const char* to) : from_file_(io_context, from, asio::stream_file::read_only), to_file_(io_context, to, asio::stream_file::write_only | asio::stream_file::create | asio::stream_file::truncate) { } void start() { do_read(); } private: void do_read() { from_file_.async_read_some(asio::buffer(data_), [this](std::error_code error, std::size_t n) { if (!error) { do_write(n); } else if (error != asio::error::eof) { std::cerr << "Error copying file: " << error.message() << "\n"; } }); } void do_write(std::size_t n) { asio::async_write(to_file_, asio::buffer(data_, n), [this](std::error_code error, std::size_t /*n*/) { if (!error) { do_read(); } else { std::cerr << "Error copying file: " << error.message() << "\n"; } }); } asio::stream_file from_file_; asio::stream_file to_file_; char data_[4096]; }; int main(int argc, char* argv[]) { try { if (argc != 3) { std::cerr << "Usage: async_file_copy \n"; return 1; } asio::io_context io_context; file_copier copier(io_context, argv[1], argv[2]); copier.start(); io_context.run(); } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; return 1; } return 0; } #else // defined(ASIO_HAS_FILE) int main() {} #endif // defined(ASIO_HAS_FILE)