For how to check your return code from another C program, you can use system from the standard library to call the executable, and WEXITSTATUS from sys/wait.h to get the return value from the result of system.

Basicallly, it's what is said in the latter half of user25148's answer above. Look at std::system's man pages for your system, and the man pages for wait (linux).

See this answer from another question for a better explanation and good example: https://stackoverflow.com/a/20193792/21742246