code correction to make RASENUM connections to work in XP

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C

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As commented on http://msdn.microsoft.com/en-us/library/windows/desktop/aa377284(v=vs.85).aspx[^] this link RasEnum code I face the same problem:

Possible inaccuracy in the Note section to lpcb param. Calling RasEnumConnections with lprasconn set to NULL to determine the required buffer size, it doesn't seem to work on Window ver < Vista.

I added the below two lines before calling the RasEnumConnections, and it works fine. Is it right? Please correct me if I am wrong.

lpRasConn = (LPRASCONN) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, dwCb); lpRasConn[0].dwSize = sizeof(RASCONN);

The below is my code, from microcsoft added with above two lines.

#include <windows.h>
#include <stdio.h>
#include "ras.h"
#include "raserror.h"
#pragma comment(lib, "rasapi32.lib")

DWORD __cdecl wmain(){

    DWORD dwCb = 0;
    DWORD dwRet = ERROR_SUCCESS;
    DWORD dwConnections = 0;
    LPRASCONN lpRasConn = NULL;

    // Call RasEnumConnections with lpRasConn = NULL. dwCb is returned with the required buffer size and 
    // a return code of ERROR_BUFFER_TOO_SMALL
    /*I ADDED THE BELOW TWO LINES */

    lpRasConn = (LPRASCONN) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, dwCb);
    lpRasConn[0].dwSize = sizeof(RASCONN);

    dwRet = RasEnumConnections(lpRasConn, &dwCb, &dwConnections);

    if (dwRet == ERROR_BUFFER_TOO_SMALL){
        // Allocate the memory needed for the array of RAS structure(s).
        lpRasConn = (LPRASCONN) HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, dwCb);
        if (lpRasConn == NULL){
            wprintf(L"HeapAlloc failed!\n");
            return 0;
        }
        // The first RASCONN structure in the array must contain the RASCONN structure size
        lpRasConn[0].dwSize = sizeof(RASCONN);

        // Call RasEnumConnections to enumerate active connections
        dwRet = RasEnumConnections(lpRasConn, &dwCb, &dwConnections);

        // If successful, print the names of the active connections.
        if (ERROR_SUCCESS == dwRet){
            wprintf(L"The following RAS connections are currently active:\n");
            for (DWORD i = 0; i < dwConnections; i++){
                         wprintf(L"%s\n", lpRasConn[i].szEntryName);
                  }
        }
        //Deallocate memory for the connection buffer
        HeapFree(GetProcessHeap(), 0, lpRasConn);
        lpRasConn = NULL;
        return 0;
    }

    // There was either a problem with RAS or there are no connections to enumerate    
    if(dwConnections >= 1){
        wprintf(L"The operation failed to acquire the buffer size.\n");
    }else{
        wprintf(L"There are no active RAS connections.\n");
    }

    return 0;
}