FIX: Wrong Exception Rethrown with Global Optimization

• The C/C++ Compiler (CL.EXE), used with:
  • Microsoft Visual C++, 32-bit Editions, version 5.0

SYMPTOMS

The wrong exception is rethrown when global optimization (/Og) is enabled. For example, in the following sample, the correct output is:

   A 1st throw
   B 2nd throw
   C 1st throw 

   A 1st throw
   B 2nd throw
   C 2nd throw 

RESOLUTION

To work around the problem, disable the global optimization on the command line or use the optimize pragma to disable the optimization for the function where the problem occurs. For example:

    #pragma optimize("g", off) 

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.This problem was corrected in Microsoft Visual C++ version 6.0.

MORE INFORMATION

Sample Code

    //test.cpp
    /* Compiler options needed : /GX  */ 
    #include <iostream>
    using namespace std;
    #pragma optimize("g", on)
    void main() {
        try
        {
            char* pStr = NULL;
            try
            {
                throw "1st throw\n";
            }
            catch( char* str )
            {
                cout << "A " << str;
                try
                {
                    throw "2nd throw\n";
                }
                catch( char* str )
                {
                    cout <<"B "<< str;
                }
                throw;
            }
        }
        catch ( char* str )
        {
            cout <<"C "<< str;
        }
    } 

Additional query words:

Keywords : kbcode kbtool kbVC500bug kbVC600fix
Version : winnt:5.0
Platform : winnt
Issue type : kbbug