Made these examples more robust. Now if the server's start() function throws an

exception it will be printed right away rather than after the user hits
the enter key.  I also removed the global server objects since that was
pretty sketchy too.

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%403713

examples/server_http_ex.cpp

@@ -13,6 +13,7 @@
 #include <sstream>
 #include <string>
 #include "dlib/server.h"
+#include "dlib/ref.h" // for ref()
 
 using namespace dlib;
 using namespace std;
@@ -91,28 +92,42 @@ class web_server : public server::http_1a_c
 
 };
 
-// create an instance of our web server
-web_server our_web_server;
-
-void thread()
+void thread(web_server& the_server)
 {
-    cout << "Press enter to end this program" << endl;
-    cin.get();
-    // this will cause the server to shut down which will in turn cause 
-    // our_web_server.start() to unblock and thus the main() function will terminate.
-    our_web_server.clear();
+    try
+    {
+        // Start the server.  start() blocks until the server is shutdown
+        // by a call to clear()
+        the_server.start();
+    }
+    catch (socket_error& e)
+    {
+        cout << "Socket error while starting server: " << e.what() << endl;
+    }
+    catch (exception& e)
+    {
+        cout << "Error while starting server: " << e.what() << endl;
+    }
 }
 
 int main()
 {
     try
     {
-        // create a thread that will listen for the user to end this program
-        thread_function t(thread);
+        // create an instance of our web server
+        web_server our_web_server;
 
         // make it listen on port 5000
         our_web_server.set_listening_port(5000);
-        our_web_server.start();
+
+        // create a thread that will start the server.   The ref() here allows us to pass 
+        // our_web_server into the threaded function by reference.
+        thread_function t(thread, ref(our_web_server));
+
+        cout << "Press enter to end this program" << endl;
+        cin.get();
+        // this will cause the server to shut down 
+        our_web_server.clear();
     }
     catch (exception& e)
     {

examples/sockets_ex.cpp

@@ -14,6 +14,7 @@
 
 #include "dlib/sockets.h"
 #include "dlib/server.h"
+#include "dlib/ref.h" // for ref()
 #include <iostream>
 
 using namespace dlib;
@@ -41,34 +42,44 @@ class serv : public server::kernel_1a_c
 
 };
 
-serv our_server;
 
-void thread()
+void thread(serv& our_server)
 {
-    cout << "Press enter to end this program" << endl;
-    cin.get();
-    // this will cause the server to shut down which will in turn cause 
-    // our_server.start() to unblock and thus the main() function will terminate.
-    our_server.clear();
+    try
+    {
+        // Start the server.  start() blocks until the server is shutdown
+        // by a call to clear()
+        our_server.start();
+    }
+    catch (socket_error& e)
+    {
+        cout << "Socket error while starting server: " << e.what() << endl;
+    }
+    catch (exception& e)
+    {
+        cout << "Error while starting server: " << e.what() << endl;
+    }
 }
 
 
-
 int main()
 {
     try
     {
-        // create a thread that will listen for the user to end this program
-        thread_function t(thread);
-
+        serv our_server;
 
         // set up the server object we have made
         our_server.set_listening_port(1234);
         our_server.set_max_connections(1000);
 
-        // start the server
-        our_server.start();
+        // create a thread that will start the server.   The ref() here allows us to pass 
+        // our_server into the threaded function by reference.
+        thread_function t(thread, ref(our_server));
 
+        cout << "Press enter to end this program" << endl;
+        cin.get();
+        // this will cause the server to shut down 
+        our_server.clear();
     }
     catch (exception& e)
     {

examples/sockstreambuf_ex.cpp

@@ -25,6 +25,7 @@
 #include "dlib/sockets.h"
 #include "dlib/server.h"
 #include "dlib/sockstreambuf.h"
+#include "dlib/ref.h"
 #include <iostream>
 
 using namespace dlib;
@@ -67,32 +68,44 @@ class serv : public server::kernel_1a_c
 
 };
 
-serv our_server;
 
-void thread()
+void thread(serv& our_server)
 {
-    cout << "Press enter to end this program" << endl;
-    cin.get();
-    // this will cause the server to shut down which will in turn cause 
-    // our_server.start() to unblock and thus the main() function will terminate.
-    our_server.clear();
+    try
+    {
+        // Start the server.  start() blocks until the server is shutdown
+        // by a call to clear()
+        our_server.start();
+    }
+    catch (socket_error& e)
+    {
+        cout << "Socket error while starting server: " << e.what() << endl;
+    }
+    catch (exception& e)
+    {
+        cout << "Error while starting server: " << e.what() << endl;
+    }
 }
 
+
 int main()
 {
     try
     {
-        // create a thread that will listen for the user to end this program
-        thread_function t(thread);
-
+        serv our_server;
 
         // set up the server object we have made
         our_server.set_listening_port(1234);
         our_server.set_max_connections(1000);
 
-        // start the server
-        our_server.start();
+        // create a thread that will start the server.   The ref() here allows us to pass 
+        // our_server into the threaded function by reference.
+        thread_function t(thread, ref(our_server));
 
+        cout << "Press enter to end this program" << endl;
+        cin.get();
+        // this will cause the server to shut down 
+        our_server.clear();
     }
     catch (exception& e)
     {