为 C++ 安装和使用 MQTT Paho 库

Question

I hope my problem is simple to resolve. I should to use mqtt protocol with my Raspberry Pi v2, so now I'm trying it with Paho libraries:

http://www.eclipse.org/paho/

I use C++ language, so I wrote first these commands

git clone http://git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.c.git
cd org.eclipse.paho.mqtt.c.git
make
sudo make install

and then these

git clone http://git.eclipse.org/gitroot/paho/org.eclipse.paho.mqtt.cpp.git
cd org.eclipse.paho.mqtt.cpp.git
make

Now I have two questions:

1. What's the library that I have to include in my file? I'm trying to compile the example in the Paho's site https://www.eclipse.org/paho/clients/cpp/ but if I include the C library "MQTTClient.h" (in the C example) it doesn't recognize the classes, like mqtt::client . I have tried to include client.h (i found it in the documentation) but the compiler doesn't find it.
2. Why the C++ procedure to start Paho's libraries doesn't install nothing? There is only the make command that creates library lib/linmqttpp.so.0.1 . I must link it in the compile command? How?

Answer 1

currently in the paho c++ in the git project it is not building correctly for new users. it creates an empty c++ library when you do a make so any code you link against that will fail with undefined method. you can check by running this command to see what is available in your library.

nm -g lib/linmqttpp.so.0.1

You will see it is empty.

Also if you copied and passed the example code from the website then it will not work. It needs other code beside what is on the website. It just gives you a code snippet.

Example code is in this directory. src/samples

paho c++ examples

Currently the make file for the sample files will fail.

I have submitted a patch just now to the project to fix the main build and the sample files build. Once that is applied the project will build correctly you can start hacking the sample files.

With regards the C++ project not installing its because there is no target in the make file to do an install. if you want for now copy the files that are created in lib to the below with sudo permissions. /usr/local/lib/

Then you can access the shared libraries from any project.