From cff61b8cf4b1f00a317600554f0dc873c498e4f3 Mon Sep 17 00:00:00 2001
From: fpagliughi <fpagliughi@mindspring.com>
Date: Fri, 16 Aug 2019 17:31:12 -0400
Subject: [PATCH] Rewrote the multi-threaded client example with a cloned
 socket.

---
 examples/tcp/tcpechomt.cpp     | 18 +++++-------------
 include/sockpp/socket.h        |  2 +-
 include/sockpp/stream_socket.h | 15 +++++++++++++++
 src/socket.cpp                 |  2 +-
 4 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/examples/tcp/tcpechomt.cpp b/examples/tcp/tcpechomt.cpp
index 712c406..d0e5730 100644
--- a/examples/tcp/tcpechomt.cpp
+++ b/examples/tcp/tcpechomt.cpp
@@ -61,9 +61,6 @@ void read_thr(sockpp::tcp_socket rdSock)
 
 	if (n < 0)
 		cout << "Read error: " << rdSock.last_error_str() << endl;
-
-	// Reset to prevent double close
-	rdSock.reset();
 }
 
 // --------------------------------------------------------------------------
@@ -91,13 +88,10 @@ int main(int argc, char* argv[])
 
 	cout << "Created a connection from " << conn.address() << endl;
 
-	// We create a read socket that uses the same handle as the connector,
-	// which we will move into the read thread. We need to be careful to
-	// reset this socket before it goes out of scope so that it doesn't
-	// close the underlying handle.
+	// We create a read thread and send it a clone (dup) of the
+	// connector socket.
 
-	sockpp::tcp_socket rdSock(conn.handle());
-	std::thread rdThr(read_thr, std::move(rdSock));
+	std::thread rdThr(read_thr, std::move(conn.clone()));
 
 	// The write loop get user input and writes it to the socket.
 
@@ -112,12 +106,10 @@ int main(int argc, char* argv[])
 	int ret = !conn ? 1 : 0;
 
 	// Shutting down the  socket will cause the read thread to exit.
+	// We wait for it to exit before we leave the app.
 
 	conn.shutdown(SHUT_WR);
-
-	// Now, we make sure the thread is done and the
-	// read socket is out of scope.
-
 	rdThr.join();
+
 	return ret;
 }
diff --git a/include/sockpp/socket.h b/include/sockpp/socket.h
index cbadcb6..4813f2f 100644
--- a/include/sockpp/socket.h
+++ b/include/sockpp/socket.h
@@ -205,7 +205,7 @@ public:
 	 * @return A new socket object that refers to the same socket as this
 	 *  	   one.
 	 */
-	socket clone();
+	socket clone() const;
 	/**
 	 * Clears the error flag for the object.
 	 * @param val The value to set the flag, normally zero.
diff --git a/include/sockpp/stream_socket.h b/include/sockpp/stream_socket.h
index 6f29115..4bce4d0 100644
--- a/include/sockpp/stream_socket.h
+++ b/include/sockpp/stream_socket.h
@@ -102,6 +102,21 @@ public:
 		base::operator=(std::move(rhs));
 		return *this;
 	}
+	/**
+	 * Creates a new stream_socket that refers to this one.
+	 * This creates a new object with an independent lifetime, but refers
+	 * back to this same socket. On most systems, this duplicates the file
+	 * handle using the dup() call.
+	 * A typical use of this is to have separate threads for reading and
+	 * writing the socket. One thread would get the original socket and the
+	 * other would get the cloned one.
+	 * @return A new stream socket object that refers to the same socket as
+	 *  	   this one.
+	 */
+	stream_socket clone() const {
+		auto h = base::clone().release();
+		return stream_socket(h);
+	}
 	/**
 	 * Open the socket.
 	 * @return @em true on success, @em false on failure.
diff --git a/src/socket.cpp b/src/socket.cpp
index 5fec722..f2fbdaf 100644
--- a/src/socket.cpp
+++ b/src/socket.cpp
@@ -110,7 +110,7 @@ void socket::destroy()
 
 // --------------------------------------------------------------------------
 
-socket socket::clone() 
+socket socket::clone() const
 {
 	socket_t h = INVALID_SOCKET;
 	#if defined(_WIN32)