Hi, im trying to compile some code right out of beej's tutorial but at compile time it comes up with a whole array of errors i'ved linked libwsock32.a, included winsock.h and ran the WSAstartup code (also cut and pasted directly out of the book) like the tutoiral says too but it's got me stumped.
Here are the errors im getting:
Code:
getaddrinfo undecleared first use of function
gai_strerror undecleared first use of function
inet_ntop undecleared first use of function
freeaddrinfo undecleared first use of function
invalid use of undefined type `struct sockaddr_in6'
forward declaration of `struct sockaddr_in6'
and heres the code:
Code:
/*
** showip.c -- show IP addresses for a host given on the command line
*/
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
//#include <sys/socket.h>
//#include <netdb.h>
//#include <arpa/inet.h>
#include <winsock.h>
struct addrinfo {
int ai_flags; // AI_PASSIVE, AI_CANONNAME, etc.
int ai_family; // AF_INET, AF_INET6, AF_UNSPEC
int ai_socktype; // SOCK_STREAM, SOCK_DGRAM
int ai_protocol; // use 0 for "any"
size_t ai_addrlen; // size of ai_addr in bytes
struct sockaddr *ai_addr; // struct sockaddr_in or _in6
char *ai_canonname; // full canonical hostname
struct addrinfo *ai_next; // linked list, next node
};
int main(int argc, char *argv[])
{
WSADATA wsaData; // if this doesn't work
// WSAData wsaData; // then try this instead
// MAKEWORD(1,1) for Winsock 1.1, MAKEWORD(2,0) for Winsock 2.0:
if (WSAStartup(MAKEWORD(1,1), &wsaData) != 0) {
fprintf(stderr, "WSAStartup failed.\n");
exit(1);
}
struct addrinfo hints, *res, *p;
int status;
char ipstr[INET6_ADDRSTRLEN];
if (argc != 2) {
fprintf(stderr,"usage: showip hostname\n");
return 1;
}
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // AF_INET or AF_INET6 to force version
hints.ai_socktype = SOCK_STREAM;
if ((status = getaddrinfo(argv[1], NULL, &hints, &res)) != 0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(status));
return 2;
}
printf("IP addresses for %s:\n\n", argv[1]);
for(p = res;p != NULL; p = p->ai_next) {
void *addr;
char *ipver;
// get the pointer to the address itself,
// different fields in IPv4 and IPv6:
if (p->ai_family == AF_INET) { // IPv4
struct sockaddr_in *ipv4 = (struct sockaddr_in *)p->ai_addr;
addr = &(ipv4->sin_addr);
ipver = "IPv4";
} else { // IPv6
struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)p->ai_addr;
addr = &(ipv6->sin6_addr);
ipver = "IPv6";
}
// convert the IP to a string and print it:
inet_ntop(p->ai_family, addr, ipstr, sizeof ipstr);
printf(" %s: %s\n", ipver, ipstr);
}
freeaddrinfo(res); // free the linked list
return 0;
}