C / C++ / MFC

char buffer[32];<br />
unsigned int i;<br />
HANDLE hPort;<br />
<br />
for( i = 1; i < 10; i++ )<br />
{<br />
  sprintf( buffer, "LPT%i", i );<br />
  hPort = CreateFile( buffer, GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL )<br />
  <br />
  if( hPort == INVALID_HANDLE_VALUE )<br />
    break; // -> i - 1 = last lpt port<br />
<br />
  CloseHandle( hPort );<br />
}<br />

DWORD dwNeed = 0;
DWORD dwPorts = 0;

BOOL b = EnumPorts (NULL, 2, NULL, dwNeed, &dwNeed, &dwPorts);
if (!b && GetLastError () == ERROR_INSUFFICIENT_BUFFER)
{
    BYTE *buf = new BYTE [dwNeed];
    memset (buf, 0, dwNeed);

    PORT_INFO_2 *p = (PORT_INFO_2 *)buf;

    b = EnumPorts (NULL, 2, buf, dwNeed, &dwNeed, &dwPorts);

    delete [] buf;
}

dwNeed = dwPorts = 0;
b = EnumPrinters (PRINTER_ENUM_LOCAL, NULL, 1, NULL, dwNeed, &dwNeed, &dwPorts);
if (!b && GetLastError () == ERROR_INSUFFICIENT_BUFFER)
{
    BYTE *buf = new BYTE [dwNeed];
    memset (buf, 0, dwNeed);
    PRINTER_INFO_1 *p = (PRINTER_INFO_1 *)buf;

    b = EnumPrinters (PRINTER_ENUM_LOCAL, NULL, 1, buf, dwNeed, &dwNeed, &dwPorts);

    delete [] buf;
}