#include "tcp.h"
     int fd,Service;
     fd = tcp_accept(Service);
     if (fd == -1)  ... an error occurred.

The C function tcp_accept() is used to accept a connection request. It returns the file descriptor for the newly created socket (fd).

A connection request is recognized when the file descriptor returned by the C function tcp_select() is the file descriptor for the passive socket returned by tcp_create_listener(). In other words, tcp_select() indicates that the passive socket created by tcp_create_listener() has input available. Since it is impossible to read from a passive socket, this means that a connection request is pending, and it is time to call tcp_accept() to accept the connection request.