使用哪个命令在C ++代码[Linux]中执行程序？

Question

Greetings,

Am new to C++ and Linux. Am looking for a command that I use to execute 3 executable programs (exe/bin) in my source code, and this what i want to do:
1. Know if the process executed successfully (return value)
2. Know process ID
3. Kill a process

I tried System(), but it doesn't return on error and no PID, also not safe. I had a quick look at fork()-exec() but is it possible not to have parent-child relation? Also, i looked into the man pages but i didn't understand :(

Please, advice me on which command I shall use.

Thank you in advance!

Answer 1

Have you looked at popen()? This might be the way to go. Try the man page.

Answer 2

system() does return the exit code of the child process the same way wait() does (or -1 on error, or 127 if it failed to spawn the shell process).

If you need to know the PID of the child and run it asynchronously, fork() followed by exec() is usually the way to go. Use popen() instead if you want to communicate with the child process through a pipe.

To alleviate the inherent parent/child relationship, you'll probably have to daemonize the child process.

Answer 3

By definition, you always have a parent-child relation when starting new programs (except when they replace your own program in the current process; you get that when calling execl without fork ing first). Functions likes system and popen internally also call fork and one of the exec variants.

Have a look at Fork and Exec tutorial from the University of Cambridge, it's pretty straight-forward and to the point. Also uses C++. Note that all the relevant calls ( fork , execl , wait ) are C POSIX functions.