inet_pton()和htonl()

#include <arpa/inet.h>

   int inet_pton(int af, const char *src, void *dst);

inet_pton - convert IPv4 and IPv6 addresses from text to binary form

#include <arpa/inet.h>

   const char *inet_ntop(int af, const void *src,
                         char *dst, socklen_t size);

inet_ntop - convert IPv4 and IPv6 addresses from binary to text form

htonl(),htons(),ntohl(),ntohs()

htonl, htons, ntohl, ntohs - convert values between host and network byte order

The htonl() function converts the unsigned integer hostlong from host byte order to network byte order.