replace system() with non-blocking function

Question

I don't want to use system() in my C program, because system(3) blocks and this is not what I want. What is the optimal way to do it?

Answer 1

Use fork() to create a new process and then use system() (or any exec function) in it. The original process will then be able to continue executing.

Answer 2

You might want to use popen. It creates new processes and allows you to redirect the process output to your own process.

Answer 3

If in windows, use the ShellExecute() function from the Windows API.

If in Unix, go for fork() then system() as mentioned.

Answer 4

I think that a quick and dirty action is to call sytem(command &). the & will spawn the new process.

Answer 5

The answer depends on what your real goal is. You don't say what platform you're on, and I know very little about Windows, so this only covers your options on linux/unix.

1. You just want to spawn another program, and don't need to interact with it. In this case, call fork(), and then in the child process run execve() (or related function).

2. You want to interact with another program. In this case, use popen().

3. You want part of your program to run as a subprocess. In this case, use fork(), and call whatever functions you need to run in the child.

4. You need to interact with part of your program running as a subprocess. Call pipe() so you have a file descriptor to communicate through, then call fork() and use the file descriptor pair to communicate. Alternatively, you could communicate through a socket, message queue, shared memory, etc.