writing to socket asymc

boost_boilerplate/CMakeLists.txt

@@ -83,3 +83,8 @@ add_executable(reading_tcp_sync
   src/chapter02_io/reading_tcp_sync.cpp
   src/sdk.h)
 target_link_libraries(reading_tcp_sync PRIVATE Threads::Threads)
+
+add_executable(writing_tcp_async
+  src/chapter02_io/writing_tcp_async.cpp
+  src/sdk.h)
+target_link_libraries(writing_tcp_async PRIVATE Threads::Threads)

boost_boilerplate/src/chapter02_io/writing_tcp_async.cpp

@@ -0,0 +1,77 @@
+#include <boost/asio.hpp>
+#include <iostream>
+#include <memory>
+
+using namespace boost;
+using namespace std;
+namespace sys = boost::system;
+namespace net = boost::asio;
+
+struct session
+{
+  std::shared_ptr<net::ip::tcp::socket> sock;
+  string buf;
+  size_t total_bytes_written;
+};
+
+void callback(const sys::error_code& ec,
+              size_t bytes_transferred,
+              std::shared_ptr<session> s)
+{
+  if (ec)
+  {
+    cout << "Error! "s << ec.what() << endl;
+
+    return;
+  }
+
+  s->total_bytes_written += bytes_transferred;
+
+  if (s->total_bytes_written == s->buf.length())
+  {
+    return;
+  }
+
+  s->sock->async_write_some(net::buffer(s->buf.c_str() + s->total_bytes_written,
+                                        s->buf.length() - s->total_bytes_written),
+                            std::bind(callback, placeholders::_1, placeholders::_2, s));
+}
+
+void WriteToSocket(std::shared_ptr<net::ip::tcp::socket> sock)
+{
+  auto s = make_shared<session>();
+
+  s->buf = string {"Hello"};
+  s->total_bytes_written = 0;
+  s->sock = sock;
+
+  s->sock->async_write_some(
+    net::buffer(s->buf),
+    bind(callback, placeholders::_1, placeholders::_2, s)
+    );
+}
+
+int main()
+{
+  string raw_ip_address = "127.0.0.1"s;
+  uint16_t port_num = 3333;
+
+  try
+  {
+    net::ip::tcp::endpoint ep(net::ip::address::from_string(raw_ip_address), port_num);
+
+    net::io_context ios;
+    auto sock = make_shared<net::ip::tcp::socket>(ios, ep.protocol());
+
+    sock->connect(ep);
+
+    WriteToSocket(sock);
+    ios.run();
+  }
+  catch (sys::system_error& e)
+  {
+    cout << "Error! " << e.what() << endl;
+  }
+
+  return EXIT_SUCCESS;
+}