what's the use of 0 in wait system call?

Question

Hi,
The syntax for the wait system call is pid= wait(&var) where pid is the process id of child and var is the variable which will contain the reason for exiting child.
But what happens when we use wait((int *)0)? What does it exactly mean?
Thank you.

Answer 1

It means that the programmer is not interested in getting child exit code. (int*)0 means NULL.