C++定义自己的错误代码（FormatMessage）

The FormatMessage function can be used to obtain error message strings for the system error codes returned by GetLastError, as shown in the following sample code.

LPVOID lpMsgBuf;FormatMessage(     FORMAT_MESSAGE_ALLOCATE_BUFFER |     FORMAT_MESSAGE_FROM_SYSTEM |     FORMAT_MESSAGE_IGNORE_INSERTS,    NULL,    GetLastError(),    MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language    (LPTSTR) &lpMsgBuf,    0,    NULL );// Process any inserts in lpMsgBuf.// ...// Display the string.MessageBox( NULL, (LPCTSTR)lpMsgBuf, "Error", MB_OK | MB_ICONINFORMATION );// Free the buffer.LocalFree( lpMsgBuf );

CSerialPort串口类中自己定义的错误代码程序如下：（Remon Spekreijse写的一个串口类， 地址在：  
 http://codeguru.earthweb.com/network/serialport.shtml）

void CSerialPort::ProcessErrorMessage(char* ErrorText)
{
 char *Temp = new char[200];
 
 LPVOID lpMsgBuf;

 FormatMessage( 
  FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
  NULL,
  GetLastError(),
  MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
  (LPTSTR) &lpMsgBuf,
  0,
  NULL 
 );

 sprintf(Temp, "WARNING:  %s Failed with the following error: /n%s/nPort: %d/n", (char*)ErrorText, lpMsgBuf, m_nPortNr); 
 MessageBox(NULL, Temp, "Application Error", MB_ICONSTOP);

 LocalFree(lpMsgBuf);
 delete [] Temp;
}