ZMQ_ROUTER_NOTIFY doesn't have a context and doesn't play nice with protocols. with ZMQ_DISCONNECT_MSG we can set it to a protocol message, like DISCONNECT in majordomo. Router will send it when a peer is disconnected. Another advantage of ZMQ_DISCONNECT_MSG is that it also works on inproc.
Together with ZMQ_HEARTBEAT it allows to build very reliable protocols, and much simpler as well.
When using ZMQ_HEARTBEAT one still needs to implement application-level heartbeat in order to know when to send a hello message.
For example, with the majordomo protocol, the worker needs to send a READY message when connecting to a broker. If the connection to the broker drops, and the heartbeat recognizes it the worker won't know about it and won't send the READY msg.
To solve that, the majordomo worker still has to implement heartbeat. With this new option, whenever the connection drops and reconnects the hello message will be sent, greatly simplify the majordomo protocol, as now READY and HEARTBEAT can be handled by zeromq.
* Allow CMAKE to generate ws and wss transports
I guess there is little use of just ws transport, so by default
GnuTLS (and libsodium) are enabled
* cmake libzmq including wss transport (ubuntu 19.10 and ubuntu 19.10 + wsl 1.0)
test_security_fails (libsodium assert !?)
* updated relicense
* make external libs gnutls nss sodium optional
* #ifdef WSS classes and functions, build test*ws* only if correct libs are included, warning if libs not present
* make libsodium optional
* cmake fix tests TIPC transport
* clang-format pointed out a wrongly placed #ifdef
* GnuTLS before 3.6.7 is not safe
* msvc doesn't agree with strlen in array declaration, test_socks now at least compiles on windows
* windows: libsodium build fails, missing include dirs set by env var
* ws transport test only works when GnuTLS is found
* Fixed condition to use NSS / built in SHA1, so that test_ws_transport should now pass, also when GnuTLS is not found
Solution: a new socket type, called PEER. Very similar to SERVER, but can only connect to other PEERs. Also a new zmq_connect_peer method, that connect and return a routing-id in thread-safe and atomic operation
Solution: if all peers of a socket are >= 3.1 use sub/cancel commands
instead of the old 0/1 messages.
For backward compatibility, move the handling of 0/1 or sub/cancel
command strings to the encoders, so that the right thing can be done
depending on the protocol version.
Do not set the command flag until the encoder, so that we can handle
the inproc case (which skips the encoder).
Solution: fix handling of _starting and _terminate flags
Add tests for this situation.
Clarify documentation of zmq_ctx_shutdown and zmq_socket.
Fixes#3792
* Problem: if IPC enabled libzmq does not compile when in uwp build
* Problem 10.0.##### can be valid windows target versions
* Problem: No builds are triggered on uwp platform
* Problem: epoll is set before UWP platform is checked
* Problem: used wrong CMAKE_SYSTEM_NAME specifier
* Problem: build tests fails during cmake configure
* Use Win32 build step for Win32-uwp platform
* Disable compile options that produce warnings that leads to a ci fail
* winnt version is set by cmake, no need for redefinition in windows.hpp
* Eliminate all warning according Incremental and opt:icf are specified
* Prefer to disable opt flags in debug config rather than incremental linking
* CMAKE_GENERATOR should not include uwp definition
* Add release build with uwp configuration
* Problem: pointer potentially uninitialized
Solution: now if the first frame in a multipart message is not subscribe/unsubscribe,
the rest of the parts are also considered to be not subscribe/unsubscribe.
Now only the first part in a multipart message will be treated as subscribe/unsubscribe.
The rest will be considered user messages regardless of the first byte.
