Dynamically executing and terminating external programs with C++

I need to execute processes with still being in control of each process. I want to create a class which stores the threads or pids or what ever is necessary to do so.

I currently have a program which executes one external application with the C function execvp and also loads the environment from a shell script. So my current program is blocking. But I need to be able to keep it freely running and only by time I terminate a currently running or start a new external application.

My current approach would be to create a thread, which uses the execve function. But then the thread would be blocking as far as I can see.

The code which might be in the thread (with variables then):

char *argv[] = { "/bin/bash", "-c", "myApplication", 0 };
execve(argv[0], &argv[0], environment.data());

The applications called are probably not fixed in the code their names will be given by an external setup file, including parameters.

Now my actual question, is there a better way to "manage" external applications like that in c++? Some ready solution (class, library)? And if not how do I terminate the thread if this is the actual way. Using the terminate call is said to be bad practice, that's what I often read.

I hope this is now specific enough for the forum, because I do not know how to get more specific anymore. If you need more hints what I want to create here, feel free to ask in the comments.

Update:

to DBus & others:

Additional information I do not wrote all of the processes I want to start! So it will be used to start 3rd party applications, which even if I have the code, do not want to change.

via Chebli Mohamed