C ++ socket UDP broadcast in Windows

Receive broadcast message end:

# Include "stdafx. H "# include <iostream> # include <winsock2.h> # pragma comment (Lib," ws2_32.lib ") const int max_buf_len = 255; using namespace STD; int _ tmain (INT argc, _ tchar * argv []) {word wversionrequested; wsadata; int err; wversionrequested = makeword (2, 2); err = wsastartup (wversionrequested, & wsadata! = 0) {return-1;} If (lobyte (wsadata. wversion )! = 2 | hibyte (wsadata. wversion )! = 2) {wsacleanup (); Return-1;} socket clientsock = socket (af_inet, sock_dgram, 0); If (invalid_socket = clientsock) {err = wsagetlasterror (); printf ("socket error: % d \ n", err); wsacleanup (); Return-1 ;}// create a local address and bind sockaddr_in sin; sin. sin_family = af_inet; sin. sin_addr.s_un.s_addr = htonl (inaddr_any); sin. sin_port = htons (7001); If (BIND (clientsock, (sockaddr *) & sin, sizeof (SIN ))! = 0) {err = wsagetlasterror (); printf ("BIND error: % d \ n", err); closesocket (clientsock); wsacleanup (); Return-1 ;} sockaddr_in clientaddr; int addrlen = sizeof (clientaddr); int nsize; char recvbuff [1024]; memset (recvbuff, 0, 1024); While (1) {nsize = recvfrom (clientsock, recvbuff, 1024, 0, (sockaddr *) & clientaddr, & addrlen); If (nsize = socket_error) {err = wsagetlasterror (); printf ("Recv error: % d \ n ", err); break;} recvbuff [nsize] = '\ 0'; printf (" % s \ n ", recvbuff);} closesocket (clientsock ); wsacleanup (); Return 0 ;}

Send broadcast message end:

# Include "stdafx. H "# include <iostream> # include <stdio. h >#include <winsock2.h> # pragma comment (Lib, "ws2_32.lib") using namespace STD; const int max_buf_len = 255; int _ tmain (INT argc, _ tchar * argv []) {word wversionrequested; wsadata wasdata; // pointer to the winsocket information structure int err; wversionrequested = makeword (2, 2); // initialize the Winsock library, prerequisites for using Socket: Err = wsastartup (wversionrequested, & wasdata); If (Err! = 0) {return-1;} If (lobyte (wasdata. wversion )! = 2 | hibyte (wasdata. wversion )! = 2) {wsacleanup (); Return-1;} socket conn_sock = socket (af_inet, sock_dgram, 0); If (conn_sock = invalid_socket) {err = wsagetlasterror (); printf ("socket error: % d \ n", err); closesocket (conn_sock); wsacleanup (); Return-1;} bool bopt = true; // enable the broadcast option setsockopt (conn_sock, sol_socket, so_broadcast, (char *) & bopt, sizeof (bopt); // set the address sockaddr_in saudpserv; memset (& saudpserv, 0, sizeof (saudpserv); saudpserv. sin_family = af_inet; saudpserv. sin_addr.s_un.s_addr = htonl (inaddr_broadcast); saudpserv. sin_port = htons (7001); int nsize = sizeof (sockaddr_in); char buff [max_buf_len]; memset (buff, 0, max_buf_len); int nloop = 0; char * IP = NULL; while (1) {nloop ++; sprintf (buff, "message % d", nloop); int nsendsize = sendto (conn_sock, buff, strlen (buff), 0, (sockaddr *) & saudpserv, nsize); If (nsendsize = socket_error) {err = wsagetlasterror (); printf ("sendto error: % d \ n ", err); closesocket (conn_sock); wsacleanup (); Return-1;} printf (" Send: % s \ n ", buff ); sleep (5000);} closesocket (conn_sock); wsacleanup (); Return 0 ;}