Porting Beej to Windows,

This is a discussion on Porting Beej to Windows, within the Networking/Device Communication forums, part of the General Programming Boards category; I've mostly figured out how to port Beejs guide to windows. I'm trying out the "Gethostbyname" lookup program. And I ...

  1. #1
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    Porting Beej to Windows,

    I've mostly figured out how to port Beejs guide to windows.

    I'm trying out the "Gethostbyname" lookup program. And I keep getting linker errors saying,

    Undefined reference to "herror"

    My source code is as follows, and I'm linking to libwsock32.a
    I'm compiling in Dev-C++ 4.9.8.0

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <winsock.h>
    #include <errno.h>
    int main(int argc, char *argv[])
    {
        WSADATA wsaData; // if this doesn’t work
        //WSAData wsaData; // then try this instead
        if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0) 
        {
            fprintf(stderr, "WSAStartup failed.\n");
            exit(1);
        }
    
    struct hostent *h;
        if (argc != 2) 
        { // error check the command line
            fprintf(stderr,"usage: getip address\n");
            exit(1);
        }
        if ((h=gethostbyname(argv[1])) == NULL) 
        { // get the host info
            herror("gethostbyname");
            exit(1);
        }
        WSACleanup();
    
        printf("Host name : %s\n", h->h_name);
        printf("IP Address : %s\n", inet_ntoa(*((struct in_addr *)h->h_addr)));
    
    
    
        system("PAUSE");	
        return 0;
    }


    Thank you for the help
    Michael



    PS: If I comment out the line refering to herror, it compiles and runs fine....
    Last edited by m.mixon; 06-24-2006 at 05:37 PM. Reason: additional info

  2. #2
    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    Truthfully, never heard of herror(). All the man pages I can find say it's deprecated. Chances are there's not a Window's equivalent (though I could be wrong), but at any rate, it seems to be error handling. If it is, Winsock errors are different from Unix ones. You can (and perhaps should) substitute it with your own error function, perhaps a fprintf() to stderr.
    The herror() function writes a message to the diagnostic output consisting of the string parameter s, the constant string ": ", and a message corresponding to the value of h_errno.
    So, basically what you pass + ":" + a message depending on h_error, a global variable probably not there in Winsock.
    EDIT: Yeah, not there as far as I can tell. Use WSAGetLastError().

    Oh, and you don't call WSACleanup() on error.
    Last edited by Cactus_Hugger; 06-24-2006 at 09:57 PM.
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