Problem: REQ socket with ZMQ_REQ_RELAXED does not report ZMQ_POLLOUT when queried for events after first message.

Solution: Check for strictness before returning false if no reply has been received.

Solution: Update errno value after calling usleep()

Solution: unified Windows & non-Windows code further

Solution: reduced code duplication by introducing local variables and
new function trigger_events

same fds

Solution: cache results of get_fd_family

iteration even if not used

Solution: Move wsa_events closer to usage

Change ZMQ_THREAD_AFFINITY to ZMQ_THREAD_AFFINITY_CPU_ADD/ZMQ_THREAD_AFFINITY_CPU_REMOVE. Avoid prefix thread names when no prefix was set.

Solution: create referencing blob_t

Solution: use std::map::emplace instead, where available

* Problem: excessive memory allocations around blob_t

Solution: redefine blob_t as a custom type, and use reference/move
semantics where possible

Solution: add "milliseconds"

* Add ZMQ_THREAD_NAME_PREFIX ctx option

* Background thread scheduling 

- add ZMQ_THREAD_AFFINITY ctx option; set all thread scheduling options
from the context of the secondary thread instead of using the main
process thread context!
- change ZMQ_THREAD_PRIORITY to support setting NICE of the background
thread when using SCHED_OTHER

Solution: add ZMQ_ZAP_ENFORCE_DOMAIN to hide backward incompatible
change and make it disabled by default.
In a future release that breaks API compatibility we can then switch
the default to enabled in order to achieve full RFC compatibility.

Fixes #2762

Solution: remove unused zap_ipc_creds boolean variable

Solution: fix it

Solution: wrap bitwise ANDs in brackets as the static analyzer suggests

Solution: take a copy of the file descriptor before setting it to
retired_fd.

Solution: Don't unlink file on close

File may not belong to the socket at that point.

On FreeBSD the sysmbol __FreeBSD_kernel__ is only defines if a
specific param.h file is included, unlike Debian/kFreeBSD where this
symbol is always defined.  So also compile the FreeBSD specific code
if __FreeBSD__ is defined for FreeBSD 11 & 12 compatibility.
Signed-off-by: Christopher Hall <hsw@ms2.hinet.net>

Solution: replaced by "routing id"

Solution: differentiate propertly between ZMTP property names and ZeroMQ API property names

Solution: fix zmq_draft.h

Solution: replaced by "routing id"

Solution: Renamed, but support querying the property by its old name

Solution: Replaced by "routing_id"

Solution: renamed routing_id fields in pipe_t, renamed ZMQ_CONNECT_RID to ZMQ_CONNECT_ROUTING_ID

Solution: replace by "routing id"

Solution: when a connection breaks and ZMQ_RECONNECT_IVL is set to -1,
which means a reconnection will not be attempted, send a message from
the I/O thread to the application thread to make the socket call
term_endpoint, which is the equivalent of manually calling
zmq_disconnect.
This way subsequent zmq_connect call to the same endpoint will attempt
again to do a connection.
Otherwise, for some socket types like SUBs, those new connects will
fail as the endpoint is recorded, despite the connection having been
permanently closed.

Add test cases to exercise this corner case with TCP and IPC.

mechanisms

Solution: uniformly require a ZAP domain to be set to activate ZAP
handling, clarify comment on Stonehouse pattern

Solution: emit events as expected by tests, and refuse connections when
ZAP is required but no handler started

Addresses #2711 partially

zmq::socket_poller_t::wait() had an important set of common lines
between POLL and SELECT variant.

Solution: refactor zmq::socket_poller_t::wait() and add the
following methods:

zmq::socket_poller_t::zero_trail_events()
zmq::socket_poller_t::check_events()
zmq::socket_poller_t::adjust_timeout()
Signed-off-by: Marc Sune <mardevel@gmail.com>

Solution: Renamed, but support querying the property by its old name

Solution: Replaced by "routing_id"

Solution: renamed routing_id fields in pipe_t, renamed ZMQ_CONNECT_RID to ZMQ_CONNECT_ROUTING_ID

Solution: replace by "routing id"

Solution: fix it

Solution: fix it