Handling Critical Errors in Windows-Based Application (69027)

SUMMARY

The Windows SetErrorMode() function controls whether Windows handles MS-DOS Function 24H errors or allows the calling application to handle them. Listed below is an example of an MS-DOS Function 24H error and Windows's method for handling the error: if an application attempts to access drive A and there is no disk in that drive, Windows displays the System Error message box "Cannot read from drive A: (Cancel) (Retry)."

Calling SetErrorMode() allows the application to handle these messages rather than defaulting to the System Error message box.

The following code fragment demonstrates this process:

  SetErrorMode(1);   // Allow application to handle system error
      ...
     /* If error occurs, handle it appropriately. */ 
      ...
   SetErrorMode(0);   // Windows will display the standard
                      // INT 24H error message box for any other
                      // System Errors.