Exec() and Fork()

Question

So i created ac program in unix. This is what it does.

1)It forks a process.

Child Process: Performs execv() on a alarm clock program which prints "Alarm rang" after 'x' seconds

Parent Process: Performs waitPID on child above. Then exits.

Output: So i ran it and i received the "Alarm rang after x seconds"

Everything is working fine. But now what i want is for the child process to run in the background. Meaning i do not want to see its output. but i want it to run and exit.

Answer 1

To make the child process run in the background, you need to make it a daemon process .

There are few steps to follow to make it a daemon process..

1. Fork off the parent process
2. Change file mode mask (umask)
3. Open any logs for writing
4. Create a unique Session ID (SID)
5. Change the current working directory to a safe place
6. Close standard file descriptors

For a better explanation, see this .