Treat accept errors as non-fatal.

asio/src/examples/allocation/server.cpp

@@ -199,11 +199,12 @@ public:
     if (!error)
     {
       new_session->start();
-      new_session.reset(new session(io_service_));
-      acceptor_.async_accept(new_session->socket(),
-          boost::bind(&server::handle_accept, this, new_session,
-            asio::placeholders::error));
     }
+
+    new_session.reset(new session(io_service_));
+    acceptor_.async_accept(new_session->socket(),
+        boost::bind(&server::handle_accept, this, new_session,
+          asio::placeholders::error));
   }
 
 private:

asio/src/examples/buffers/reference_counted.cpp

@@ -92,11 +92,12 @@ public:
     if (!error)
     {
       new_session->start();
-      new_session.reset(new session(io_service_));
-      acceptor_.async_accept(new_session->socket(),
-          boost::bind(&server::handle_accept, this, new_session,
-            asio::placeholders::error));
     }
+
+    new_session.reset(new session(io_service_));
+    acceptor_.async_accept(new_session->socket(),
+        boost::bind(&server::handle_accept, this, new_session,
+          asio::placeholders::error));
   }
 
 private:

asio/src/examples/chat/chat_server.cpp

@@ -181,6 +181,11 @@ public:
       const tcp::endpoint& endpoint)
     : io_service_(io_service),
       acceptor_(io_service, endpoint)
+  {
+    start_accept();
+  }
+
+  void start_accept()
   {
     chat_session_ptr new_session(new chat_session(io_service_, room_));
     acceptor_.async_accept(new_session->socket(),
@@ -194,11 +199,9 @@ public:
     if (!error)
     {
       session->start();
-      chat_session_ptr new_session(new chat_session(io_service_, room_));
-      acceptor_.async_accept(new_session->socket(),
-          boost::bind(&chat_server::handle_accept, this, new_session,
-            asio::placeholders::error));
     }
+
+    start_accept();
   }
 
 private:

asio/src/examples/echo/async_tcp_echo_server.cpp

@@ -36,6 +36,7 @@ public:
           asio::placeholders::bytes_transferred));
   }
 
+private:
   void handle_read(const asio::error_code& error,
       size_t bytes_transferred)
   {
@@ -67,7 +68,6 @@ public:
     }
   }
 
-private:
   tcp::socket socket_;
   enum { max_length = 1024 };
   char data_[max_length];
@@ -79,6 +79,12 @@ public:
   server(asio::io_service& io_service, short port)
     : io_service_(io_service),
       acceptor_(io_service, tcp::endpoint(tcp::v4(), port))
+  {
+    start_accept();
+  }
+
+private:
+  void start_accept()
   {
     session* new_session = new session(io_service_);
     acceptor_.async_accept(new_session->socket(),
@@ -92,18 +98,15 @@ public:
     if (!error)
     {
       new_session->start();
-      new_session = new session(io_service_);
-      acceptor_.async_accept(new_session->socket(),
-          boost::bind(&server::handle_accept, this, new_session,
-            asio::placeholders::error));
     }
     else
     {
       delete new_session;
     }
+
+    start_accept();
   }
 
-private:
   asio::io_service& io_service_;
   tcp::acceptor acceptor_;
 };

asio/src/examples/fork/process_per_connection.cpp

@@ -43,11 +43,16 @@ private:
 
   void handle_signal_wait()
   {
-    // Reap completed child processes so that we don't end up with zombies.
-    int status = 0;
-    while (waitpid(-1, &status, WNOHANG) > 0) {}
+    // Only the parent process should check for this signal. We can determine
+    // whether we are in the parent by checking if the acceptor is still open.
+    if (acceptor_.is_open())
+    {
+      // Reap completed child processes so that we don't end up with zombies.
+      int status = 0;
+      while (waitpid(-1, &status, WNOHANG) > 0) {}
 
-    start_signal_wait();
+      start_signal_wait();
+    }
   }
 
   void start_accept()
@@ -76,6 +81,9 @@ private:
         // acceptor. It remains open in the parent.
         acceptor_.close();
 
+        // The child process is not interested in processing the SIGCHLD signal.
+        signal_.cancel();
+
         start_read();
       }
       else
@@ -93,6 +101,7 @@ private:
     else
     {
       std::cerr << "Accept error: " << ec.message() << std::endl;
+      start_accept();
     }
   }
 

asio/src/examples/http/server/server.cpp

@@ -21,8 +21,7 @@ server::server(const std::string& address, const std::string& port,
     signals_(io_service_),
     acceptor_(io_service_),
     connection_manager_(),
-    new_connection_(new connection(io_service_,
-          connection_manager_, request_handler_)),
+    new_connection_(),
     request_handler_(doc_root)
 {
   // Register to handle the signals that indicate when the server should exit.
@@ -43,9 +42,8 @@ server::server(const std::string& address, const std::string& port,
   acceptor_.set_option(asio::ip::tcp::acceptor::reuse_address(true));
   acceptor_.bind(endpoint);
   acceptor_.listen();
-  acceptor_.async_accept(new_connection_->socket(),
-      boost::bind(&server::handle_accept, this,
-        asio::placeholders::error));
+
+  start_accept();
 }
 
 void server::run()
@@ -57,17 +55,30 @@ void server::run()
   io_service_.run();
 }
 
+void server::start_accept()
+{
+  new_connection_.reset(new connection(io_service_,
+        connection_manager_, request_handler_));
+  acceptor_.async_accept(new_connection_->socket(),
+      boost::bind(&server::handle_accept, this,
+        asio::placeholders::error));
+}
+
 void server::handle_accept(const asio::error_code& e)
 {
+  // Check whether the server was stopped by a signal before this completion
+  // handler had a chance to run.
+  if (!acceptor_.is_open())
+  {
+    return;
+  }
+
   if (!e)
   {
     connection_manager_.start(new_connection_);
-    new_connection_.reset(new connection(io_service_,
-          connection_manager_, request_handler_));
-    acceptor_.async_accept(new_connection_->socket(),
-        boost::bind(&server::handle_accept, this,
-          asio::placeholders::error));
   }
+
+  start_accept();
 }
 
 void server::handle_stop()

asio/src/examples/http/server/server.hpp

@@ -35,6 +35,9 @@ public:
   void run();
 
 private:
+  /// Initiate an asynchronous accept operation.
+  void start_accept();
+
   /// Handle completion of an asynchronous accept operation.
   void handle_accept(const asio::error_code& e);
 

asio/src/examples/http/server2/server.cpp

@@ -19,8 +19,7 @@ server::server(const std::string& address, const std::string& port,
   : io_service_pool_(io_service_pool_size),
     signals_(io_service_pool_.get_io_service()),
     acceptor_(io_service_pool_.get_io_service()),
-    new_connection_(new connection(
-          io_service_pool_.get_io_service(), request_handler_)),
+    new_connection_(),
     request_handler_(doc_root)
 {
   // Register to handle the signals that indicate when the server should exit.
@@ -41,9 +40,8 @@ server::server(const std::string& address, const std::string& port,
   acceptor_.set_option(asio::ip::tcp::acceptor::reuse_address(true));
   acceptor_.bind(endpoint);
   acceptor_.listen();
-  acceptor_.async_accept(new_connection_->socket(),
-      boost::bind(&server::handle_accept, this,
-        asio::placeholders::error));
+
+  start_accept();
 }
 
 void server::run()
@@ -51,17 +49,23 @@ void server::run()
   io_service_pool_.run();
 }
 
+void server::start_accept()
+{
+  new_connection_.reset(new connection(
+        io_service_pool_.get_io_service(), request_handler_));
+  acceptor_.async_accept(new_connection_->socket(),
+      boost::bind(&server::handle_accept, this,
+        asio::placeholders::error));
+}
+
 void server::handle_accept(const asio::error_code& e)
 {
   if (!e)
   {
     new_connection_->start();
-    new_connection_.reset(new connection(
-          io_service_pool_.get_io_service(), request_handler_));
-    acceptor_.async_accept(new_connection_->socket(),
-        boost::bind(&server::handle_accept, this,
-          asio::placeholders::error));
   }
+
+  start_accept();
 }
 
 void server::handle_stop()

asio/src/examples/http/server2/server.hpp

@@ -37,6 +37,9 @@ public:
   void run();
 
 private:
+  /// Initiate an asynchronous accept operation.
+  void start_accept();
+
   /// Handle completion of an asynchronous accept operation.
   void handle_accept(const asio::error_code& e);
 

asio/src/examples/http/server3/server.cpp

@@ -21,7 +21,7 @@ server::server(const std::string& address, const std::string& port,
   : thread_pool_size_(thread_pool_size),
     signals_(io_service_),
     acceptor_(io_service_),
-    new_connection_(new connection(io_service_, request_handler_)),
+    new_connection_(),
     request_handler_(doc_root)
 {
   // Register to handle the signals that indicate when the server should exit.
@@ -42,9 +42,8 @@ server::server(const std::string& address, const std::string& port,
   acceptor_.set_option(asio::ip::tcp::acceptor::reuse_address(true));
   acceptor_.bind(endpoint);
   acceptor_.listen();
-  acceptor_.async_accept(new_connection_->socket(),
-      boost::bind(&server::handle_accept, this,
-        asio::placeholders::error));
+
+  start_accept();
 }
 
 void server::run()
@@ -63,16 +62,22 @@ void server::run()
     threads[i]->join();
 }
 
+void server::start_accept()
+{
+  new_connection_.reset(new connection(io_service_, request_handler_));
+  acceptor_.async_accept(new_connection_->socket(),
+      boost::bind(&server::handle_accept, this,
+        asio::placeholders::error));
+}
+
 void server::handle_accept(const asio::error_code& e)
 {
   if (!e)
   {
     new_connection_->start();
-    new_connection_.reset(new connection(io_service_, request_handler_));
-    acceptor_.async_accept(new_connection_->socket(),
-        boost::bind(&server::handle_accept, this,
-          asio::placeholders::error));
   }
+
+  start_accept();
 }
 
 void server::handle_stop()

asio/src/examples/http/server3/server.hpp

@@ -36,6 +36,9 @@ public:
   void run();
 
 private:
+  /// Initiate an asynchronous accept operation.
+  void start_accept();
+
   /// Handle completion of an asynchronous accept operation.
   void handle_accept(const asio::error_code& e);
 

asio/src/examples/iostreams/daytime_server.cpp

@@ -34,8 +34,12 @@ int main()
     for (;;)
     {
       tcp::iostream stream;
-      acceptor.accept(*stream.rdbuf());
-      stream << make_daytime_string();
+      asio::error_code ec;
+      acceptor.accept(*stream.rdbuf(), ec);
+      if (!ec)
+      {
+        stream << make_daytime_string();
+      }
     }
   }
   catch (std::exception& e)

asio/src/examples/nonblocking/third_party_lib.cpp

@@ -208,8 +208,9 @@ private:
     if (!error)
     {
       new_connection->start();
-      start_accept();
     }
+
+    start_accept();
   }
 
   tcp::acceptor acceptor_;

asio/src/examples/porthopper/server.cpp

@@ -56,13 +56,13 @@ public:
       asio::async_read(*socket, request->to_buffers(),
           boost::bind(&server::handle_control_request, this,
             asio::placeholders::error, socket, request));
-
-      // Start waiting for a new control connection.
-      tcp_socket_ptr new_socket(new tcp::socket(acceptor_.get_io_service()));
-      acceptor_.async_accept(*new_socket,
-          boost::bind(&server::handle_accept, this,
-            asio::placeholders::error, new_socket));
     }
+
+    // Start waiting for a new control connection.
+    tcp_socket_ptr new_socket(new tcp::socket(acceptor_.get_io_service()));
+    acceptor_.async_accept(*new_socket,
+        boost::bind(&server::handle_accept, this,
+          asio::placeholders::error, new_socket));
   }
 
   // Handle a new control request.

asio/src/examples/serialization/server.cpp

@@ -72,20 +72,13 @@ public:
       conn->async_write(stocks_,
           boost::bind(&server::handle_write, this,
             asio::placeholders::error, conn));
+    }
 
-      // Start an accept operation for a new connection.
-      connection_ptr new_conn(new connection(acceptor_.get_io_service()));
-      acceptor_.async_accept(new_conn->socket(),
-          boost::bind(&server::handle_accept, this,
-            asio::placeholders::error, new_conn));
-    }
-    else
-    {
-      // An error occurred. Log it and return. Since we are not starting a new
-      // accept operation the io_service will run out of work to do and the
-      // server will exit.
-      std::cerr << e.message() << std::endl;
-    }
+    // Start an accept operation for a new connection.
+    connection_ptr new_conn(new connection(acceptor_.get_io_service()));
+    acceptor_.async_accept(new_conn->socket(),
+        boost::bind(&server::handle_accept, this,
+          asio::placeholders::error, new_conn));
   }
 
   /// Handle completion of a write operation.

asio/src/examples/ssl/server.cpp

@@ -107,10 +107,7 @@ public:
     context_.use_private_key_file("server.pem", asio::ssl::context::pem);
     context_.use_tmp_dh_file("dh512.pem");
 
-    session* new_session = new session(io_service_, context_);
-    acceptor_.async_accept(new_session->socket(),
-        boost::bind(&server::handle_accept, this, new_session,
-          asio::placeholders::error));
+    start_accept();
   }
 
   std::string get_password() const
@@ -118,21 +115,27 @@ public:
     return "test";
   }
 
+  void start_accept()
+  {
+    session* new_session = new session(io_service_, context_);
+    acceptor_.async_accept(new_session->socket(),
+        boost::bind(&server::handle_accept, this, new_session,
+          asio::placeholders::error));
+  }
+
   void handle_accept(session* new_session,
       const asio::error_code& error)
   {
     if (!error)
     {
       new_session->start();
-      new_session = new session(io_service_, context_);
-      acceptor_.async_accept(new_session->socket(),
-          boost::bind(&server::handle_accept, this, new_session,
-            asio::placeholders::error));
     }
     else
     {
       delete new_session;
     }
+
+    start_accept();
   }
 
 private:

asio/src/examples/timeouts/server.cpp

@@ -365,6 +365,11 @@ public:
     subscriber_ptr bc(new udp_broadcaster(io_service_, broadcast_endpoint));
     channel_.join(bc);
 
+    start_accept();
+  }
+
+  void start_accept()
+  {
     tcp_session_ptr new_session(new tcp_session(io_service_, channel_));
 
     acceptor_.async_accept(new_session->socket(),
@@ -377,12 +382,9 @@ public:
     if (!ec)
     {
       session->start();
-
-      tcp_session_ptr new_session(new tcp_session(io_service_, channel_));
-
-      acceptor_.async_accept(new_session->socket(),
-          boost::bind(&server::handle_accept, this, new_session, _1));
     }
+
+    start_accept();
   }
 
 private:

asio/src/examples/tutorial/daytime3/server.cpp

@@ -92,8 +92,9 @@ private:
     if (!error)
     {
       new_connection->start();
-      start_accept();
     }
+
+    start_accept();
   }
 
   tcp::acceptor acceptor_;

asio/src/examples/tutorial/daytime7/server.cpp

@@ -91,8 +91,9 @@ private:
     if (!error)
     {
       new_connection->start();
-      start_accept();
     }
+
+    start_accept();
   }
 
   tcp::acceptor acceptor_;

asio/src/examples/windows/transmit_file.cpp

@@ -132,8 +132,9 @@ private:
     if (!error)
     {
       new_connection->start();
-      start_accept();
     }
+
+    start_accept();
   }
 
   tcp::acceptor acceptor_;

asio/src/tests/performance/server.cpp

@@ -155,6 +155,11 @@ public:
     acceptor_.bind(endpoint);
     acceptor_.listen();
 
+    start_accept();
+  }
+
+  void start_accept()
+  {
     session* new_session = new session(io_service_, block_size_);
     acceptor_.async_accept(new_session->socket(),
         boost::bind(&server::handle_accept, this, new_session,
@@ -166,15 +171,13 @@ public:
     if (!err)
     {
       new_session->start();
-      new_session = new session(io_service_, block_size_);
-      acceptor_.async_accept(new_session->socket(),
-          boost::bind(&server::handle_accept, this, new_session,
-            asio::placeholders::error));
     }
     else
     {
       delete new_session;
     }
+
+    start_accept();
   }
 
 private: