Q153793: How To Check for a Remote Access Service Connection

Article: Q153793
Product(s): Microsoft FoxPro
Version(s): 3.00 3.00b
Operating System(s): 
Keyword(s): kbvfp300 kbvfp300b kbvfp600
Last Modified: 04-AUG-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 6.0 
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SUMMARY
=======

This article describes some windows APIs related to a Remote Access Service. The
tasks described in this article are available as commands in Microsoft FoxPro
version 2.6 for Windows, as well as versions 3.0 and 3.0b. This article
describes how to verify the RAS (Remote Access Service) while using the remote
view.

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

Often, you can anticipate the run-time errors when you work with the remote view
due to the bad telephone connection. You can shield from these errors by
including the error-handling code included in this article using APIs.

It is possible to check whether a Remote Access Service has been disconnected.
This verification can be controlled by using some API calls (RasEnumConnections
and RasGetConnectStatus). In this article, the customized API routine was
written using Microsoft Visual C++ 4.0 to check the status of RAS connections.

The following sample program illustrates the contents of the .DLL file written in
Microsoft Visual C++ 4.0 and shows a way to verify the connection of RAS
successfully through the Win32 SDK.

NOTE: This sample program illustrates many Microsoft Visual C++ commands. The use
of these commands is beyond the scope of Microsoft FoxPro Product Support. Users
with substantial experience using API routines should be able to write the
following sample .DLL file. For this sample .DLL file to work, you need a .DEF
file to export the rasnt function.

Sample C++ Program (DLL)
------------------------

     #include <stdio.h>
     #include <windows.h>
     #include <ras.h>

     HANDLE hInst;
     HWND   hDlg;
     HANDLE hHeap;

     BOOL APIENTRY DllMain(HANDLE hInst, DWORD ul_reason_being_called, LPVOID
     lpReserved)
     {
         return 1;
             UNREFERENCED_PARAMETER(hInst);
             UNREFERENCED_PARAMETER(ul_reason_being_called);
             UNREFERENCED_PARAMETER(lpReserved);
     }

     int APIENTRY rasnt(void)
     {
         LPRASCONN     lpRasConn = NULL;
         DWORD   cbBuf = 0;
         DWORD   cConn = 0;
         DWORD   dwRet = 0;
         HRASCONN   hrasconn;
         RASCONNSTATUS rasStatus;
         UINT    ndx;

         // enumerate connections
         cbBuf = sizeof(RASCONN);
         if ( (lpRasConn = ( LPRASCONN ) malloc((UINT)cbBuf)) != NULL)
         {
             lpRasConn->dwSize = sizeof( RASCONN );
             dwRet = RasEnumConnections( lpRasConn, &cbBuf, &cConn );
        for (ndx = 0; ndx < cConn; ndx++)
        {
            // get to HRASCONN
            hrasconn = lpRasConn[ndx].hrasconn;

            // get connection status
            rasStatus.dwSize = sizeof(RASCONNSTATUS);
            dwRet = RasGetConnectStatus( hrasconn, &rasStatus );
            if ( dwRet ) return 0;
            else
            {
           if (rasStatus.rasconnstate == RASCS_Connected) return 1;
           else return 0;
            }
        }
         }

         return 0;
     }

Sample DEF File
---------------

     LIBRARY   rasnt

     CODE    PRELOAD MOVEABLE DISCARDABLE
     DATA    PRELOAD SINGLE

     EXPORTS
         rasnt      @2

Sample Visual FoxPro Program
----------------------------

     DECLARE integer rasnt IN RASNT.DLL
     retval = rasnt()

     IF retval = 1 THEN
        WAIT WINDOW "there is connection"
     ELSE
        WAIT WINDOW "there is no connection"
     ENDIF

Sample Program (Notes)
----------------------

- To create a .DLL file in Visual C++, please refer to a Help file in Microsoft
  Visual C++ 4.0.

- Note that the Rasnt.dll should be in the same directory as your FoxPro
  project, or should be in the path of the Windows Win32 directory.

In order to compile the above DLL properly, you need to include RASAPI32.LIB.

Additional query words: VFoxWin

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Keywords          : kbvfp300 kbvfp300b kbvfp600 
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP600
Version           : 3.00 3.00b

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