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POprogram crashes when i try find MAC address
 

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    <p>i have a client server application in MFC using UDP where the server displays the IP address of connected clients in a listbox. If i run the client and server on the same computer the program displays the MAC address <strong>but if i try to run the client on a different computer the program crashes</strong>. Here are the 3 functions. I have an event handler for the listbox that displays the MAC address in a second listbox when an IP address is selected. PrintMACFromIP is the code for getting the MAC address</p> <pre><code>void CmfcServerDlg::OnLbnSelchangeListClientaddr() { BYTE Address[MAX_ADAPTER_ADDRESS_LENGTH]; int nIndex = m_ClientAddrList.GetCurSel(); if(nIndex &lt; 0) return; CString s1; m_ClientAddrList.GetText(nIndex, s1); PrintMACFromIP(s1); } void CmfcServerDlg::PrintMACaddress(unsigned char MACData[]) { CString strText; strText.Format("%02X-%02X-%02X-%02X-%02X-%02X\n",MACData[0], MACData[1], MACData[2], MACData[3], MACData[4], MACData[5]); m_ClientIdList.AddString(strText); } void CmfcServerDlg:: PrintMACFromIP(const CString &amp;selected_ip_adr) { IP_ADAPTER_INFO AdapterInfo[16]; DWORD dwBufLen = sizeof(AdapterInfo); DWORD dwStatus = GetAdaptersInfo( AdapterInfo, &amp;dwBufLen); assert(dwStatus == ERROR_SUCCESS); PIP_ADAPTER_INFO pAdapterInfo = AdapterInfo; bool found = false; do { const IP_ADDR_STRING *addr_str = &amp;pAdapterInfo-&gt;IpAddressList; while(addr_str != NULL) { if(selected_ip_adr == addr_str-&gt;IpAddress.String) { found = true; break; } } if(found) { PrintMACaddress(pAdapterInfo-&gt;Address); break; } else { pAdapterInfo = pAdapterInfo-&gt;Next; } } while(pAdapterInfo); } </code></pre>
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    1. COHave you tried putting debug statements or tracing it down through an IDE? It more than likely is due to the use of a null pointer but you haven't provided enough information such as dumped core or stacktraces. You should also check if `pAdapterInfo` is NULL before using it.
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    2. COi debugged it and found it gets stuck in the while loop. so is there something wrong with the code?
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    3. COWhere in the while loop?
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