How to use getaddrinfo() on windows

Question

I'm trying to build my APP with mingw+msys.

My code usee winsock. When I compile it I take following error message:

$ gcc -o sample sample.c -lws2_32
    C:\Users\user\AppData\Local\Temp\ccsdWlQR.o:sample.c:(.text+0xeb): undefined reference to `getaddrinfo'
    collect2.exe: error: ld returned 1 exit status

This is my code that is migrated from Linux with changing some headers.

#include <stdio.h>
#include <WinSock2.h>
#include <WS2tcpip.h>

main(int argc,char *argv[])
{
    WSADATA wsaData;
    WSAStartup(MAKEWORD(2,2), &wsaData);

    printf("Hello world with winsock");

    int sock;
    char *hostAddress;
    struct addrinfo hints,*res;
    int err;
    memset(&hints,0,sizeof(hints));
    hints.ai_family = AF_UNSPEC; 
    hints.ai_socktype = SOCK_DGRAM;
    getaddrinfo("127.0.0.1",12345,&hints,&res);

    printf("getaddrinfo %s\n",strerror(errno));
    printf("getaddrinfo : %s \n",gai_strerror(err));


    struct sockaddr_in *addr;
    struct addrinfo *rp;
    for (rp = res; rp != NULL; rp = rp->ai_next) {
        addr = (struct sockaddr_in *)rp->ai_addr; 
        printf("dstPort  = %d\n",ntohs(addr->sin_port));
        printf("dstAddr  = %s\n",inet_ntoa((struct in_addr)addr->sin_addr));
        hostAddress = inet_ntoa((struct in_addr)addr->sin_addr);    
    }
    WSACleanup( );                                    

}

How can I use gettarrinfo() in Windows?

This is the additional information that message is changed after trying dgreenday's article.

sample.c:22:2: warning: passing argument 2 of 'getaddrinfo' makes pointer from i
nteger without a cast [enabled by default]
  getaddrinfo("124.0.0.1",12345,&hints,&res);
  ^
In file included from sample.c:4:0:
c:\mingw\include\ws2tcpip.h:391:12: note: expected 'const char *' but argument i
s of type 'int'
 int WSAAPI getaddrinfo (const char*,const char*,const struct addrinfo*,

Answer 1

I suspect that you simply have an out of date SDK, and the import library supplied in your SDK does not include getaddrinfo. Your program, compiled the way you describe links fine on my mingw system.

Either update your mingw system, or create an import library that does contain getaddrinfo.

Note that:

getaddrinfo("124.0.0.1",12345,&hints,&res);

should be:

getaddrinfo("124.0.0.1","12345",&hints,&res);

And you are not checking for errors correctly. You must take notice of the value returned by getaddrinfo. It is not appropriate to ignore that and then go on to check errno.