Trouble building paho.mqtt.cpp

[helo-ch]

I'm trying to install paho.mqtt.cpp on a VM running CentOs 6. I have successfully installed and used paho.mqtt.c, but when I try to build paho.mqtt.cpp I get a lot of errors after the make command :

[  7%] Building CXX object src/CMakeFiles/OBJS.dir/async_client.cpp.o
In file included from /home/heloise/paho.mqtt.cpp/src/mqtt/async_client.h:28,
                 from /home/heloise/paho.mqtt.cpp/src/async_client.cpp:19:
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:37: erreur: expected nested-name-specifier before ‘byte’
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:37: erreur: ‘byte’ has not been declared
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:37: erreur: expected ‘;’ before ‘=’ token
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:37: erreur: expected unqualified-id before ‘=’ token
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:40: erreur: expected nested-name-specifier before ‘string’
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:40: erreur: ‘string’ has not been declared
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:40: erreur: expected ‘;’ before ‘=’ token
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:40: erreur: expected unqualified-id before ‘=’ token
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:42: erreur: expected nested-name-specifier before ‘binary’
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:42: erreur: ‘binary’ has not been declared
/home/heloise/paho.mqtt.cpp/src/mqtt/types.h:42: erreur: expected ‘;’ before ‘=’ token

.....and so on for quite a while.

The errors end by

make[2]: *** [src/CMakeFiles/OBJS.dir/async_client.cpp.o] Erreur 1
make[1]: *** [src/CMakeFiles/OBJS.dir/all] Erreur 2
make: *** [all] Erreur 2

I have no idea what went wrong since I was only following the build instructions? The C++ compiler on my system is g++.

Thanks in advance for your help.

Héloïse

[fpagliughi]

What version of g++? I believe the default compiler on CentOS 6 was pretty old. The Paho library requires a conforming C++11 compiler, so for g++, that's at least v4.8, I believe. What is shown with the command:

g++ --version

[helo-ch]

It appears that I was indeed using g++ 4.4.7.

However I just updated it to g++ 4.8.2 and I still get the same errors after running make.

[fpagliughi]

Are you sure that 4.8.2 is now the default compiler?
What is the version of CMake that you're using? You need 3.1 or newer.

If all of that looks good, maybe you need to regenerate the CMake cache? Delete your build directory and re-run CMake.

If that fails, post the full output from the initial CMake command, at least up until the first few errors.

And then, try a build using the default GNU Makefile in the top directory. Just:

cd paho.mqtt.cpp
make

[helo-ch]

I regenerated the CMake cache and it worked, thank you!