The inet_network() call interprets character strings representing addresses expressed in standard dotted decimal notation and returns numbers suitable for use as a network number.
#include <manifest.h>
#include <bsdtypes.h>
#include <socket.h>
#include <in.h>
#include <inet.h>
unsigned long inet_network(char *cp)
The network number is returned in host byte order.
inet_addr(), inet_lnaof(), inet_makeaddr(), inet_ntoa()