Knowledge Base

BUG: Windows 95 Access Violation Error After Disabling CTRL+C

Article ID: 137379

Article Last Modified on 3/21/2005

Microsoft Win32 Application Programming Interface, when used with:
- Microsoft Windows 95
- Microsoft Windows 98 Standard Edition
- Microsoft Windows Millennium Edition

This article was previously published under Q137379

SYMPTOMS

In a Win32 environment, a console application can be terminated by pressing CTRL+C. To disable CTRL+C input, a console application can call the SetConsoleCtrlHandler(NULL, TRUE) API function.

When this API function is called in Windows NT, CTRL+C is ignored if pressed. However, when it is called in Windows 95, pressing CTRL+C generates an Access Violation error. Similarly, when this API is called in Windows 95, pressing CTRL+BREAK generates an Access Violation error.

RESOLUTION

There are two alternatives when you want to disable CTRL+C and avoid generating an Access Violation error:

Install a console control handler to capture and ignore the CTRL+C keypress:

      SetConsoleCtrlHandler(MyHandler, TRUE);
      BOOL MyHandler(DWORD dwEventType)
      {
         if ( dwEvnetType == CTRL_C_EVENT
         if ( dwEventType == CTRL_C_EVENT )
            return TRUE;   // CTRL+C handle by function
         else
            return FALSE;  // pass to next handler
      }

Disable CTRL+C by disabling the ENABLE_PROCESSED_INPUT console mode. Disabling the ENABLE_PROCESSED_INPUT console mode then reports CTRL+C to the input buffer, not the system:
```
      SetConsoleMode( hConsoleHandle,
          (Mode & ~ ENABLE_PROCESSED_INPUT) );
					
```

STATUS

Microsoft has confirmed this to be a bug in the products listed at the beginning of this article.

Keywords: kbbug kbconsole kbprogramming kbkernbase KB137379