GetHostByName

This is a discussion on GetHostByName within the C++ Programming forums, part of the General Programming Boards category; Code: #include <windows.h> #include <cctype> #include <iostream> int main(){ //---------------------- // Declare and initialize variables hostent* remoteHost; char* host_name; unsigned ...

  1. #1
    Reverse Engineer maxorator's Avatar
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    GetHostByName

    Code:
    #include <windows.h>
    #include <cctype>
    #include <iostream>
    int main(){
    //----------------------
    // Declare and initialize variables
    hostent* remoteHost;
    char* host_name;
    unsigned int addr;
    
    //----------------------
    // User inputs name of host
    printf("Input name of host: ");
    
    //----------------------
    // Allocate 64 byte char string for host name
    host_name = (char*) malloc(sizeof(char)*64);
    fgets(host_name, 64, stdin);
    
    // If the user input is an alpha name for the host, use gethostbyname()
    // If not, get host by addr (assume IPv4)
    if (isalpha(host_name[0])) {   /* host address is a name */
      // if hostname terminated with newline '\n', remove and zero-terminate 
      if (host_name[strlen(host_name)-1] == '\n') 
        host_name[strlen(host_name)-1] = '\0'; 
      remoteHost = gethostbyname(host_name);
    }
    else  { 
      addr = inet_addr(host_name);
      remoteHost = gethostbyaddr((char *)&addr, 4, AF_INET);
    }
    
    if (WSAGetLastError() != 0) {
      if (WSAGetLastError() == 11001)
      printf("Host not found...\nExiting.\n");
    }
    else{
      printf("error#:%ld\n", WSAGetLastError());
    }
    std::cout<<remoteHost.h_addr;
    system("PAUSE");
    // The remoteHost structure can now be used to
    // access information about the host
    }
    Errors:
    Code:
    Kompilaator: Consoles
    Building Makefile: "C:\Programs\Dev-Cpp\Makefile.win"
     make... käivitus
    make.exe -f "C:\Programs\Dev-Cpp\Makefile.win" all
    g++.exe -c Templates/solaris2.cpp -o Templates/solaris2.o -I"C:/PROGRAMS/DEV-CPP/lib/gcc/mingw32/3.4.2/include"  -I"C:/PROGRAMS/DEV-CPP/include/c++/3.4.2/backward"  -I"C:/PROGRAMS/DEV-CPP/include/c++/3.4.2/mingw32"  -I"C:/PROGRAMS/DEV-CPP/include/c++/3.4.2"  -I"C:/PROGRAMS/DEV-CPP/include"    -fno-access-control
    
    Templates/solaris2.cpp: In function `int main()':
    Templates/solaris2.cpp:40: error: `h_addr_list' has not been declared
    
    Templates/solaris2.cpp:40: error: request for member of non-aggregate type before '[' token
    
    Käivitus peatatud
    The part of the winsock.h header file:
    Code:
    struct  hostent {
    	char	*h_name;
    	char	**h_aliases;
    	short	h_addrtype;
    	short	h_length;
    	char	**h_addr_list;
    #define h_addr h_addr_list[0]
    };

  2. #2
    Registered User
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    the program has two problems.
    1. it does not include winsock.h. you have to include that in addition to windows.h

    2. remostHost is a pointer, so use pointer operator, not the dot operator.
    Code:
    std::cout<<remoteHost->h_addr;

  3. #3
    Reverse Engineer maxorator's Avatar
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    Thanks

  4. #4
    Reverse Engineer maxorator's Avatar
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    Well, I get illegal operation message :P

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