Solution: New class called stream_engine_base which is inherited by ws_engine, zmtp_engine and raw_engine.

Solution: apply clang-format-diff

Two issues where introduced by commit 12c4b55a:
- the proxy connection was done to the target address instead of
the proxy address
- on error the proxy connection status was not reset to unplugged

Solution: now that clang-format 6+ is used in the CI, fix it

Solution: added TODO comment for now

Solution: move unblock call to original location

Solution: restore "local" flag values in call to resolve

Fixes #3394

Solution: use tcp_open_socket function

Solution: let socks_connecter_t derive from stream_connecter_base_t and remove duplicate code

Solution: query the local address and set it

Solution: add monitor event socket option

* Problem: connecter classes do not handle ZMQ_RECONNECT_IVL of -1

Solution: Add guards to prevent a reconnect timer from starting if ZMQ_RECONNECT_IVL is -1
(Issue 3158)

Solution: introduced named constants

Problem: inconsistent naming style for private data members, conflicts with naming of local variables and member functions

Solution: apply and check _lower_case naming style for private data members

Solution: define and apply parameter naming style: lower_case_

Solution: make error handling consistent and use retired_fd to remove code duplication

Solution: replace by C++-style casts

* Fixes issue 2963, ref stream_engine.cpp:981

* Fixes issue 2963, ref socks_connecter.cpp:158

* Fixes issue 2963, ref tcp_listener.cpp:144

* Fixes issue 2963, ref tcp_connecter.cpp:423

* Fixes issue 2963, ref socks_connecter.cpp:436

* Fixes issue 2963, ref tcp_listener.cpp:179

* Fixes issue 2963, ref tcp_listener.cpp:268

* Fixes issue 2963, ref tcp_connecter.cpp:160

Solution: commit clang-format-diff

* Problem: Still need to port over more files to VxWorks 6.x

Solution: Port more files to VxWorks 6.x

* Problem: Need to port over remaining files to VxWorks 6.x. Also remove POSIX thread dependency for VxWorks (because of priority inversion problem in POSIX mutexes with VxWorks 6.x processes)

Solution: Port over remaining files to VxWorks 6.x. Also removed POSIX thread dependency for VxWorks

* Problem: Needed to modify TCP, UDP, TIPC classes with #ifdefs to be compatible with VxWorks 6.x.

Solution:  Modify TCP, UDP, TIPC classes with #ifdefs to be compatible with VxWorks 6.x

Solution: applied clang-format

Linux now supports Virtual Routing and Forwarding (VRF) as per:

https://www.kernel.org/doc/Documentation/networking/vrf.txt

In order for an application to bind or connect to a socket with an
address in a VRF, they need to first bind the socket to the VRF device:

    setsockopt(sd, SOL_SOCKET, SO_BINDTODEVICE, dev, strlen(dev)+1);

Note "dev" is the VRF device, eg. VRF "blue", rather than an interface
enslaved to the VRF.

Add a new socket option, ZMQ_BINDTODEVICE, to bind a socket to a device.
In general, if a socket is bound to a device, eg. an interface, only
packets received from that particular device are processed by the socket.

If device is a VRF device, then subsequent binds/connects to that socket
use addresses in the VRF routing table.

* Prevent DOS by asserts in TCP tuning

-Propagates socket option errors from the
tuning functions to the callers.
-Asserts a subset of error conditions during tuning,
excluding external network causes.
-Checks tuning results in 3 call sites and treats
them like failures to connect, accept, etc.

* Fix variable name

* Remove lambda requiring C++11

Solution: initialize class variable in the same order as they are
defined.

Solution: fix it

Solution: The Coverity Static Code Analyzer was used on libzmq code and found
many issues with uninitialized member variables, some redefinition of variables
hidding previous instances of same variable name and a couple of functions
where return values were not checked, even though all other occurrences were
checked (e.g. init_size() return).

Solution: Phase I - make precompiled.hpp be first file included in every source file

Solution: update to 2016

Solution: Move the macros to a private header.

LIBZMQ-195 allow explicitly setting sndbuf and rcvbuf to 0 (see https://support.microsoft.com/en-us/kb/201213)

Of course people still "can" distributed the sources under the
LGPLv3. However we provide COPYING.LESSER with additional grants.

Solution: specify these grants in the header of each source file.