DOCUMENT:Q311815  10-DEC-2001  [winnt]
TITLE   :PRB: WSACleanUp()  AV If Host Name Longer Than 54 Characters
PRODUCT :Microsoft Windows NT
PROD/VER::4.0
OPER/SYS:
KEYWORDS:kbAPI kbWinsock kbDSupport kbGrpDSNet

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Windows NT Server version 4.0 
 - Microsoft Windows NT Workstation version 4.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

When you run gethostbyname(), gethostbyaddr(), or gethostname() on a Windows NT
4.0-based computer, the API returns the correct information. However, when you
call WSACleanUp(), an access violation occurs and the program fails.

NOTE: This problem does not occur on Windows 2000.

RESOLUTION
==========

To avoid this problem, do not use host names that contain more than 54
characters.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Right-click Network Neighborhood, and then click Properties.

2. Click the Protocol tab, and then select TCP/IP.

3. Click the Properties button.

4. Click the DNS tab. Change the host name to a name that has at least 54
   characters.

5. Run the following code:

   #include <Winsock2.h>
   #include <iostream.h>

   int main(int argc,char* argv[])
   {
   	WSADATA wsaData;
   	char pStr[512]={0};
   	int ret;
   	
   	if(WSAStartup(0x0101,&wsaData)) {
   		cout<<"WSAStartup ";
   		cout << " error: ?<<WSAGetLastError()<<endl;
   		return 0;
   	}
   	cout<<argv[1]<<endl;
   		
   	if(gethostname(pStr,512)) {
   		cout<<"gethostbyname ";
   		cout << " error: ?<<WSAGetLastError()<<endl;
   		WSACleanup();
   		return 0;
   	}
   	cout<<"host name: " <<pStr<<endl;
   	
   	ret=WSACleanup ();
   	if(ret) {
   		cout<<"WSACleanup ";
   		cout << " error: ?<<WSAGetLastError()<<endl;
   		return 0;
   	}
   	return 0;
   }

An access violation occurs when the call is made to WSACleanUp().

Additional query words:

======================================================================
Keywords          : kbAPI kbWinsock kbDSupport kbGrpDSNet 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400sp6 kbWinNTS400search kbWinNTS400 kbWinNTW400SP6a
Version           : :4.0
Issue type        : kbprb

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.