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News: Windows Sockets gethostbyaddr() doesn't work
(Adapted) Winsock-Sourcen von Daniel Schwamm (11.10.1996)
Aus "Heimat des Dilettantismus"
http://www.henrys.de/daniel/index.php?cmd=texte_winsock_news-gethostbyaddr.htm
<![CDATA[
Re: Windows Sockets' gethostbyaddr() doesn't work
---------------------------------------------------------------------------
From kahn@lgk.com (Larry Kahn)
Organization Dynamics Research Corp.
Date Thu, 10 Oct 1996 01:55:40 GMT
Newsgroups microsoft.public.win95.networking,comp.os.ms-windows.networking.tcp-ip
Message-ID <a97cc$143728.6d@p6dnf.drcoffsite.com>
References 1
---------------------------------------------------------------------------
In article <325B5AD9.1093@vtools.es>, jlanyo@vtools.es says...
>
>Hi all.
>I have developed a DLL to cover IP net communications using Windows
>Sockets. Up to date, I have not any problem, until I have try to use
>gethostbyaddr() function. This always returns 0 and I'm not able to find
>out what's going on. The error code returned by WSAGetLastError is 11004
>(Valid name, no data record of requested type...). I have tried to use
>the async version of this function, and the result is the same.
>I'm sure the parameters are well, a pointer to an address in network
>byte order, its length (4 bytes), and PF_INET.
>
>Could somebody help me?
>Thanks in advance.
>
>
include <stdio.h>
#include <stdlib.h>
#include <winsock.h>
void disp_help()
{
printf("\nGet host name program V 1.1 by L. Kahn (C) 1995\n");
printf("_______________________________________________\n\n");
printf("Syntax: ghostname hostname \n");
printf("WHERE: hostname is the name or ip address of a host.\n\n");
}
void main(argc,argv)
int argc;
char **argv;
{
WORD wVersionrequired;
WSADATA WSData;
char remotename[80];
static struct sockaddr_in destination;
static struct hostent *ptrhostentry;
LPSTR plpstr;
struct in_addr *pin_addr;
int rval = 0;
wVersionrequired = MAKEWORD(1,1);
if (argc != 2)
disp_help();
else
{
/* ok assume second arg is host name */
rval = WSAStartup(wVersionrequired, &WSData);
if (rval != 0)
{
printf("Startup ERROR: could not find a usable a winsock DLL.\n");
fflush(stdout);
exit(1);
}
if (LOBYTE(WSData.wVersion) != 1 || HIBYTE(WSData.wVersion) != 1)
{
printf("Startup ERROR: could not find a winsock DLL version 1.1 or newer.\n");
fflush(stdout);
exit(1);
}
else
{
strcpy(remotename,argv[1]);
memset(&destination,0,sizeof(struct sockaddr));
destination.sin_family=AF_INET;
destination.sin_addr.s_addr = inet_addr(remotename);
if(destination.sin_addr.s_addr ==INADDR_NONE)
{
ptrhostentry = gethostbyname(remotename);
if (ptrhostentry == NULL)
{
printf("can't get entry for host name: %s\n",remotename);
fflush(stdout);
WSACleanup();
exit(1);
}
}
else
{
ptrhostentry = gethostbyaddr((LPSTR)&destination.sin_addr.s_addr,4,PF_INET);
if (ptrhostentry == NULL)
{
printf("can't get ip entry for host name: %s\n",remotename);
fflush(stdout);
WSACleanup();
exit(1);
}
}
/* if we get here we have valid entry so do it */
memcpy(&destination.sin_addr,ptrhostentry->h_addr,ptrhostentry->h_length);
printf("Translated Name is: %s\n",ptrhostentry->h_name);
while((pin_addr=(struct in_addr *)*(ptrhostentry->h_addr_list))!=NULL)
{
printf("IP Address is : %s\n",inet_ntoa(*pin_addr));
ptrhostentry->h_addr_list++;
}
while((plpstr=(LPSTR)*(ptrhostentry->h_aliases))!=NULL)
{
printf("Alias: %s\n",plpstr);
ptrhostentry->h_aliases++;
}
} /* end of ok startup */
} /* end of ok parameters */
printf("\n");
fflush(stdout);
WSACleanup();
} /* end of main */
>--
>Jose Luis Anyonuevo | Visual Tools S.A. | Tel: +34 1 5352642
>Software Engineer | Video Surveillance | Fax: +34 1 5353695
> | Almansa 62 |
>jlanyo@vtools.es | 28039 Madrid (SPAIN) | sales: nacho@vtools.es
>
--
_________________________________________________________________________
Larry Kahn __ __ __ __ Senior Software Engineer
/ \ / \ / \ / \ Dynamics Research Corp.
____________________/ __\/ __\/ __\/ __\_____________________________
___________________/ /__/ /__/ /__/ /________________________________
kahn@lgk.com / / \ / \ / \ / \ \____ kahn@drcoffsite.com
\_/ \_/ \_/ \_/ \ o \
\_____/--<
(TALK: larry@ambra.drcoffsite.com)
(FINGER: .site@ambra.drcoffsite.com for PGP public key)
_________________________________________________________________________
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