C - Notify When A Background Process Is Finished - c

Question

I am creating a small shell program, one functionality of my shell is to be able to run commands in the background.
If a job is run in the background, then a small message is shown notifying the user of the pid.
Furthermore, I want to also be able to notify the user of when the background job is done
This is my code so far:
int execArgs(char *argv[], int bg)
{
int pid ;
int child_info = -1;
if(argv[1] == "exit"){
printf("%s\n", argv[0]);
}
if ( argv[0] == NULL ) /* nothing succeeds */
return 0;
if ( (pid = fork()) == -1 )
perror("fork");
else if ( pid == 0 ){
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
execvp(argv[0], argv);
perror("cannot execute command");
exit(1);
}
else {
if(bg == 0){
if ( wait(&child_info) == -1 )
perror("wait");
}
else
printf("The Process PID:%d has started\n", pid);
}
return child_info;
}
I know the answer lies in something to do with the
pid_t return_pid = waitpid(process_id, &status, WNOHANG);
but I don't understand how to use it completely, what does 'status' mean?
I tried implementing it like this:
int execArgs(char *argv[], int bg)
{
int pid ;
int child_info = -1;
if(argv[1] == "exit"){
printf("%s\n", argv[0]);
}
if ( argv[0] == NULL ) /* nothing succeeds */
return 0;
if ( (pid = fork()) == -1 )
perror("fork");
else if ( pid == 0 ){
signal(SIGINT, SIG_DFL);
signal(SIGQUIT, SIG_DFL);
execvp(argv[0], argv);
perror("cannot execute command");
exit(1);
}
else {
if(bg == 0){
if ( wait(&child_info) == -1 )
perror("wait");
}
else
printf("The Process PID:%d has started\n", pid);
int status;
pid_t return_pid = waitpid(pid, &status, WNOHANG); /* WNOHANG def'd in wait.h */
if (return_pid == -1) {
/* error */
} else if (return_pid == 0) {
/* child is still running */
} else if (return_pid == pid) {
printf("The process PID:%d has finished\n", pid);
}
}
return child_info;
}
but it doesn't work. I have read the man pages but they are a bit cumbersome and I don't understand them.
Apologies if the answer is elsewhere on StackOverFlow, I tried searching as thoroughly as I could.