As libzmq is compiled with optional transports and security mechanisms,
there is no clean way for applications to determine what capabilities
are actually available in a given libzmq instance.
Solution: provide an API specifically for capability reporting. The
zmq_has () method is meant to be open ended. It accepts a string so
that we can add arbitrary capabilities without breaking existing
applications.
zmq.h also defines ZMQ_HAS_CAPABILITIES when this method is provided.
Applications that use ZMQ_IDENTITY can be trapped by the artificial
restriction on not using a binary zero as first byte. It's specially
nasty on random generated identities, e.g. UUIDs, as the chance of a
binary zero is low, so it will pass 255 out of 256 times.
Solution: remove the restriction.
Added modifiers reflect the following properties:
- zmq_msg_gets () does not mutate property parameter
- zmq_msg_gets () returns a pointer to memory the caller should not
modify
Specifically:
* zmq_event_t should not be used internally in libzmq, it was
meant to be an outward facing structure.
* In 4.x, zmq_event_t does not correspond to monitor events, so
I removed the structure entirely.
* man page for zmq_socket_monitor is incomplete and the example
code was particularly nasty.
* test_monitor.cpp needed rewriting, it was not clean.
Issues adressed:
- The actual data was never read from the socket, causing all even
numbered loop iterations to fail
- The socket variable was called server once
The new options allows querying the maximum allowed number of sockets.
This is system dependent and cannot be encoded in the include file as a
preprocessor macro: for ZMQ_USE_SELECT, this depends on the FD_SETSIZE
macro at time of library compilation, not at time of include file use.
When a ZMQ_STREAM socket connection is broken (intentionally, via `shutdown()`
or accidentally via client crash or network failure), there is no way for the
application to dertermine that it should drop per-connection data (such as
buffers).
This contribution makes sure the application receives a 0-length message to
notify it that the connection has been broken. This is symmetric with the
process of closing the connection from within the application (where the
application sends a 0-length message to tell ZeroMQ to close the connection).
Conflicts:
CMakeLists.txt
- This seems redundant; is there a use case for NOT providing
the IPC credentials to the ZAP authenticator?
- More, why is IPC authentication done via libzmq instead of ZAP?
Is it because we're missing the transport type on the ZAP request?
Another take on LIBZMQ-568 to allow filtering IPC connections, this time
using ZAP. This change is backward compatible. If the
ZMQ_ZAP_IPC_CREDS option is set, the user, group, and process IDs of the
peer process are appended to the address (separated by colons) of a ZAP
request; otherwise, nothing changes. See LIBZMQ-568 and zmq_setsockopt
documentation for more information.
