int socket (int family, int type, int protocol), this interface creates a socketFamily specifies the protocol family (usually af_inet), and the type parameter specifies the types of sockets: Sock_stream, SOCK_DGRAM, and Sock_raw;protocol are usually assigned the value "0".int bind (int sockfd, struct sockaddr *my_addr, int addrlen); Bind socket to IP address and portstruct SOCKADDR_IN
{
Short sin_family;
U_short Sin_port;
struct IN_ADDR sin_addr;
Char Sin_zero[8];
};an instance of a binding:struct sockaddr_in saddr;
memset (void *) &saddr,0,sizeof (SADDR));
saddr.sin_family = af_inet;
Saddr.sin_port = htons (8888); port number greater than 1024
SADDR.SIN_ADDR.S_ADDR = htonl (Inaddr_any); Bind to local IP
SADDR.SIN_ADDR.S_ADDR = inet_addr ("192.168.22.5"); Binding fixed IP
Bind (Listensocket, (struct sockaddr *) &saddr,sizeof (SADDR));int Listen (int sockfd, int backlog);SOCKFD is the server-side socket descriptor returned by the socket system call, and the backlog specifies the maximum number of requests allowed in the request queueint Accept (int sockfd, struct sockaddr *addr, int *addrlen);SOCKFD is a server socket descriptor that is being monitored, and addr is usually a pointer to a sockaddr_in variable that holds the client address that made the connection request the Connect () function is used to establish a TCP connection to the remote server with its function prototype:
int Connect (int sockfd, struct sockaddr *serv_addr, int addrlen); int Send (int sockfd, const void *msg, int len, int flags); int recv (int sockfd,void *buf,int len,unsigned int flags);int sendto (int sockfd, const void *msg,int len,unsigned int flags,const struct sockaddr *to,int tolen);Used for data transfer on non-connected sockets (Sock_dgram/sock_raw) int recvfrom (int sockfd,void *buf,int len,unsigned int flags,struct sockaddr *from,int *fromlen);Close (SOCKFD);Close () is an operation on a socket that is closed after the process cannot access the socket.IP, DNS, and other related functionsin_addr_t inet_addr (const char * strptr); Converts the string IP address to the IPV4 address structure in_addr value char * INET_NTOA (struct in_addr * addrptr); Converts the IPV4 address structure in_addr value to a string IP struct hostent *gethostbyname (const char *name); Conversion of domain names and IP addresses:
UNIX Network programming Socket API
