Before your program does exit(0);

What and, How do you check before your program does exit(1);
to free resource you used - socket, memory... - completely?

Here is my code using exit(1);
as you see newfd is socket id.

Code:

                        switch(iFno)
                        {
                                case 1:
                                        if(!IPcheck(newfd, psIP, psAstr[0])) {
                                                exit(1);
                                        }
                                        WorkFno1(newfd, psData, psAstr, z);
                                        break;

                                case 2:
                                        if(!IPcheck(newfd, psIP, psAstr[1])) {
                                                exit(1);
                                        }
                                        WorkFno2(newfd, psData, psAstr, z);
                                        break;

                                case 2100:
                                        if(!IPcheck(newfd, psIP, psAstr[3])) {
                                                exit(1);
                                        }
                                        WorkFno2100(newfd, psData, psAstr, z);
                                        break;

                                default:
                                        //Format Error
                                        HonSend(newfd, "1,0\n");
                                        shutdown(newfd,2);
                        }

Thanks for reading.

Code:

<headers>

int main ( void )
{
	/* code */
	close();
	return 0;
}

int close ( void )
{
	/* free stuff */
	exit(1)
}