Question

I am calling a command via system(command) call. But no other code is executed after this system() call.

Why is so? I thought, system() would create a child process for “command” execution and my program (parent of “command”-child) will continue executing code after that.

Am I not understanding system() correctly?

code:

printf("before \n");
system("tail -f filename");       /* long lived - never returns */
printf("after \n");

Here, I do not see after getting printed ever.

Answer 1

The system(3) function causes your process to wait for the completion of the child.

Edit 0:

You have to use the classic pair of fork(2) and execve(2) for what you want to do. You might also check whether your C library provides POSIX spawn(3).

Edit 1:

Look into waitpid(2) to keep the parent around.