VS2019编译完成的paho.mqtt.cpp库

# Eclipse Paho MQTT C++ Client Library [](https://travis-ci.org/eclipse/paho.mqtt.cpp) This repository contains the source code for the [Eclipse Paho](http://eclipse.org/paho) MQTT C++ client library on memory-managed operating systems such as Linux/Posix and Windows. This code builds a library which enables C++11 applications to connect to an [MQTT](http://mqtt.org) broker, publish messages to the broker, and to subscribe to topics and receive published messages. The library has the following features: - Support for MQTT v5, v3.1.1, and v 3.1 - TCP, SSL/TLS, and WebSocket transports - Message persistence - Automatic reconnect - Offline buffering - High availability - Blocking and non-blocking API's This code requires the [Paho C library](https://github.com/eclipse/paho.mqtt.c) by Ian Craggs, et al., specifically version 1.3.1 or possibly later. ## Latest News To keep up with the latest announcements for this project, or to ask questions: **Twitter:** [@eclipsepaho](https://twitter.com/eclipsepaho) and [@fmpagliughi](https://twitter.com/fmpagliughi) **EMail:** [Eclipse Paho Mailing List](https://accounts.eclipse.org/mailing-list/paho-dev) **Mattermost:** [Eclipse Mattermost Paho Channel](https://mattermost.eclipse.org/eclipse/channels/paho) ### New Features in Paho C++ v1.1 - MQTT v5 support: - **Properties** - New `property` class acts something like a std::variant to hold a property of any supported type. - New `properties` class is a collection type to hold all the properties for a single transmitted packet. - Properties can be added to outbound messages and obtained from received messages. - Properties can also be obtained from server responses to requests such as from a _connect_ call. These are available in the `token` objects when they complete. - The client object tracks the desired MQTT version that the app requested and/or is currently connected at. Internally this is now required by the `response_options` the need to distinguish between pre-v5 and post-v5 callback functions. - MQTT v5 reason codes for requests are available via `token` objects when they complete. They are also available in `exception` objects that are thrown by tokens. - Support for subscibe options, like no local subscriptions, etc. - Sample applications were added showing how to do basic Remote Procedure Calls (RPC's) with MQTT v5 using the *RESPONSE_TOPIC* and *CORRELATION_DATA* properties. These are *rpc_math_cli* and *rpc_math_srvr* in the _src/samples_ directory. - A sample "chat" application was added, showing how to use subscribe options, such as "no local". - More descriptive error messages (PR #154), integrated into the `mqtt::exception` class. MQTT v5 reason codes are also included in the exceptions when an error occurs. - Applications can (finally) get server responses from the various ACK packets. These are available through the tokens after they complete, as `connect_response`, `subscribe_response`, and `unsubscribe_response`. - The `topic` objects can be used to subscribe. - Applications can register individual callback functions instead of using a `callback` interface object. This allows easy use of lambda functions for callbacks. - The connect options can take a LWT as a plain message, via `connect_options::set_will_message()` ### _Catch2_ Unit Tests Unit tests are being converted to use _Catch2_ for the test framework. The legacy unit tests are still using _CppUnit_, compiled into a separate test executable. If everything goes well with _Catch2_, the older unit tests will be ported to _Catch2_ as well. _Catch2_ can be found here: [Catch2](https://github.com/catchorg/Catch2) ## Contributing Contributions to this project are gladly welcomed. Before submitting a Pull Request, please keep two things in mind: - This is an official Eclipse project, so it is required that all contributors sign an [Eclipse Contributor Agreement (ECA)](https://www.eclipse.org/legal/ECA.php) - Please submit all Pull Requests against the _develop_ branch (not master). For full details, see [CONTRIBUTING.md](https://github.com/eclipse/paho.mqtt.cpp/blob/master/CONTRIBUTING.md). ## Building from source *GNU Make and autotools were deprecated and removed in the v1.1 release.* _CMake_ is a cross-platform build system suitable for Unix and non-Unix platforms such as Microsoft Windows. It is now the only supported build system. The Paho C++ library requires the Paho C library, v1.3.1 or greater, to be built and installed first. More information below. CMake allows for options to direct the build. The following are specific to Paho C++: Variable | Default Value | Description ------------ | ------------- | ------------- PAHO_BUILD_SHARED | TRUE (Linux), FALSE (Win32) | Whether to build the shared library PAHO_BUILD_STATIC | FALSE (Linux), TRUE (Win32) | Whether to build the static library PAHO_BUILD_DOCUMENTATION | FALSE | Create and install the HTML based API documentation (requires Doxygen) PAHO_BUILD_SAMPLES | FALSE | Build sample programs PAHO_BUILD_TESTS | FALSE | Build the unit tests. (This currently requires both _CppUnit_ and _Catch2_) PAHO_WITH_SSL | TRUE (Linux), FALSE (Win32) | Flag that defines whether to build ssl-enabled binaries too In addition, the C++ build might commonly use `CMAKE_PREFIX_PATH` to help the build system find the location of the Paho C library. ### Unix and Linux On *nix systems CMake creates Makefiles. The build process currently supports a number of Unix and Linux flavors. The build process requires the following tools: * CMake v3.5 or newer * GCC v4.8 or newer or Clang v3.9 or newer * GNU Make On Debian based systems this would mean that the following packages have to be installed: ``` $ sudo apt-get install build-essential gcc make cmake cmake-gui cmake-curses-gui ``` If you will be using secure sockets (and you probably should): ``` $ sudo apt-get install libssl-dev ``` Building the documentation requires doxygen and optionally graphviz to be installed: ``` $ sudo apt-get install doxygen graphviz ``` Unite tests are currently being built using both _CppUnit_ and _Catch2_. The _CppUnit_ tests are being deprecated and replaced with _Catch2_ equivalents. In the meantime, however, both systems are required to build the tests. ``` $ sudo apt-get install libcppunit-dev ``` _Catch2_ can be found here: [Catch2](https://github.com/catchorg/Catch2) Before building the C++ library, first, build and install the Paho C library: ``` $ git clone https://github.com/eclipse/paho.mqtt.c.git $ cd paho.mqtt.c $ git checkout v1.3.1 $ cmake -Bbuild -H. -DPAHO_WITH_SSL=ON -DPAHO_ENABLE_TESTING=OFF $ sudo cmake --build build/ --target install $ sudo ldconfig ``` This builds with SSL/TLS enabled. If that is not desired, omit the `-DPAHO_WITH_SSL=ON`. If you installed the C library on a non-standard path, you might want to pass it as value to the `CMAKE_PREFIX_PATH` option. Using these variables CMake can be used to generate your Makefiles. The out-of-source build is the default on CMake. Therefore it is recommended to invoke all build commands inside your chosen build directory. An example build session might look like this: ``` $ git clone https://github.com/eclipse/paho.mqtt.cpp $ cd paho.mqtt.cpp $ cmake -Bbuild -H. -DPAHO_BUILD_DOCUMENTATION=TRUE -DPAHO_BUILD_SAMPLES=TRUE $ sudo cmake --build build/ --target install $ sudo ldconfig ``` If you did not install Paho C library to a default system location or you want to build against a different version, use the `CMAKE_PREFIX_PATH` to specify its install location: ``` $ cmake -Bbuild -H. -DPAHO_BUILD_DOCUMENTATION=TRUE -DPAHO_BUILD_SAMPLES=TRUE \ -DCMAKE_PREFIX_PATH=../../pa