KB166719 - FIX: Wrong Exception Rethrown with Global Optimization

Article ID: 166719

Article Last Modified on 7/5/2005

Microsoft Visual C++ 5.0 Enterprise Edition
Microsoft Visual C++ 5.0 Professional Edition

This article was previously published under Q166719

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

However, if global optimization (/Og) is enabled, the output is:

   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 that this is a problem in the Microsoft products that are 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;
        }
    }

Keywords: kbbug kbfix kbvc600fix kbcode KB166719