KB120967 - BUG: Try Blocks Within a Switch Statement Behave Incorrectly

Article ID: 120967

Article Last Modified on 7/5/2005

Microsoft Visual C++ 2.0 Professional Edition
Microsoft Visual C++ 4.0 Standard Edition
Microsoft Visual C++ 4.1 Subscription
Microsoft Visual C++ 4.2 Professional Edition
Microsoft Visual C++ 5.0 Standard Edition
Microsoft Visual C++ 6.0 Service Pack 5

This article was previously published under Q120967

SYMPTOMS

A try block within a switch statement may cause the exception to be handled incorrectly, as illustrated by the sample code in the MORE INFORMATION section below.

CAUSE

The compiler doesn't recognize catch blocks within the switch statement. Therefore, the compiler attempts to link the try block to the next catch block outside the switch. In the sample code in the More Information section below, the second catch block is executed after the exception is thrown.

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

Sample Code

The following sample code demonstrates the problem:

/* Compile options needed: /GX
*/ 

#include <stdio.h>

void main(void)
{
   int i = 0;

   try
   {
      switch ( i )
      try
      {
         case 0:
            throw i;
      }
      catch( int )
      {
      /* Should be caught here but isn't */ 
         printf( "Passed.\n" );
      }
   }
   catch (...)
   {
   /* Is caught here incorrectly */ 
      printf( "Failed.\n" );
   }
}

Additional query words: kbVC400bug 9.00 10.00 10.10 10.20 exception handling

Keywords: kbbug kbnoupdate kbcpponly kbcode kbcompiler KB120967