how to exit a child process - _exit() vs. exit
You should definitely use _Exit(). exit() calls the functions you added with atexit() and deletes files created with tmpfile(). Since the parent process is really the one that wants these things done when it exists, you should call _Exit(), which does none of these.
Notice _Exit() with a capital E. _exit(2) is probably not what you want to call directly. exit(3) and _Exit(3) will call this for you. If you don't have _Exit(3), then yes, _exit() is what you wanted.
execvp will exit the child if successfull so you don't have to exit.
On execve failure I simply use exit(EXIT_FAILURE); in the child.
Edit : i found that after some research : http://www.unixguide.net/unix/programming/1.1.3.shtml
So it's looks like it's better to use _exit() in a fork child specially when you are in C++ :pThanks for your question i learned something :D