Fixed win32 issue with WSAStartup

 - ctx constructor was calling mailbox_t constructor implicitly
 - moved WSAStartup and WSACleanup to be outside constructor/destructor
Signed-off-by: Pieter Hintjens <ph@imatix.com>

src/ctx.cpp

@@ -39,17 +39,6 @@ zmq::ctx_t::ctx_t (uint32_t io_threads_) :
 {
     int rc;
 
-#ifdef ZMQ_HAVE_WINDOWS
-    //  Intialise Windows sockets. Note that WSAStartup can be called multiple
-    //  times given that WSACleanup will be called for each WSAStartup.
-    WORD version_requested = MAKEWORD (2, 2);
-    WSADATA wsa_data;
-    rc = WSAStartup (version_requested, &wsa_data);
-    zmq_assert (rc == 0);
-    zmq_assert (LOBYTE (wsa_data.wVersion) == 2 &&
-        HIBYTE (wsa_data.wVersion) == 2);
-#endif
-
     //  Initialise the array of mailboxes. Additional three slots are for
     //  internal log socket and the zmq_term thread the reaper thread.
     slot_count = max_sockets + io_threads_ + 3;
@@ -109,12 +98,6 @@ zmq::ctx_t::~ctx_t ()
     //  needed as mailboxes themselves were deallocated with their
     //  corresponding io_thread/socket objects.
     free (slots);
-    
-#ifdef ZMQ_HAVE_WINDOWS
-    //  On Windows, uninitialise socket layer.
-    int rc = WSACleanup ();
-    wsa_assert (rc != SOCKET_ERROR);
-#endif
 }
 
 int zmq::ctx_t::terminate ()

src/zmq.cpp

@@ -234,6 +234,19 @@ void *zmq_init (int io_threads_)
     }
 #endif
 
+#ifdef ZMQ_HAVE_WINDOWS
+    //  Intialise Windows sockets. Note that WSAStartup can be called multiple
+    //  times given that WSACleanup will be called for each WSAStartup.
+   //  We do this before the ctx constructor since its embedded mailbox_t
+   //  object needs Winsock to be up and running.
+    WORD version_requested = MAKEWORD (2, 2);
+    WSADATA wsa_data;
+    int rc = WSAStartup (version_requested, &wsa_data);
+    zmq_assert (rc == 0);
+    zmq_assert (LOBYTE (wsa_data.wVersion) == 2 &&
+        HIBYTE (wsa_data.wVersion) == 2);
+#endif
+
     //  Create 0MQ context.
     zmq::ctx_t *ctx = new (std::nothrow) zmq::ctx_t ((uint32_t) io_threads_);
     zmq_assert (ctx);
@@ -250,6 +263,12 @@ int zmq_term (void *ctx_)
     int rc = ((zmq::ctx_t*) ctx_)->terminate ();
     int en = errno;
 
+#ifdef ZMQ_HAVE_WINDOWS
+    //  On Windows, uninitialise socket layer.
+    rc = WSACleanup ();
+    wsa_assert (rc != SOCKET_ERROR);
+#endif
+
 #if defined ZMQ_HAVE_OPENPGM
     //  Shut down the OpenPGM library.
     if (pgm_shutdown () != TRUE)