Function wait 

pub fn wait(pid: Pid) -> Result<usize, ErrorStatus>

Waits for the process with the resource id pid to exit and returns the exit code of the process

Returns

• Ok(exit_code) if the target process was found, was a child of self, and was awaited successfully

• ErrorStatus::InvalidPid if the target process doesn’t exist at the time of wait

• ErrorStatus::MissingPermissions if the target process isn’t a child of self