Re: [Cppunit-devel] Partial answer: 2.3) Why does the test ExceptionTest.testAssignment failed in CppUnit test

[Baptiste L. <bl...@cl...>]

Thanks for pointing that out Phil. I went a little further, and while the
operator =() does weird stuff it does the job. When checkIsSame() is called,
members of the original and assigned exception are equal (m_message members
that are used by CppUnit::Exception::what() have the same value).

I tracked down the problem, and it occurs in checkIsSame():

void
ExceptionTest::checkIsSame( CppUnit::Exception &e,
                            CppUnit::Exception &other )
{
  std::string eWhat( e.what() );
  std::string otherWhat( other.what() );
---
004054DA   mov         esi,esp
004054DC   lea         eax,[ebp-38h]
004054DF   push        eax
004054E0   mov         ecx,dword ptr [ebp+0Ch]
004054E3   mov         edx,dword ptr [ecx]
004054E5   mov         edi,esp
004054E7   mov         ecx,dword ptr [ebp+0Ch]
004054EA   call        dword ptr [edx+4]

// here std::exception::what() is called instead of
CppUnit::Exception::what() which returns the m_message member.
// The weird stuff is that e.what() does call CppUnit::Exception::what()
correctly...
---
  CPPUNIT_ASSERT_EQUAL( eWhat, otherWhat );
  CPPUNIT_ASSERT( e.sourceLine() == other.sourceLine() );
}

No matter how I twist think around, for other, it is always
std::exception::what() that is called !

// Inverting the order of initialisation doesn't change a thing...
  const char *otherWhat = other.what();
  const char *eWhat = e.what();

  CPPUNIT_ASSERT_EQUAL( std::string(eWhat), std::string(otherWhat) );

Any idea ?

Baptiste.

----- Original Message -----
From: "Phil Taylor" <phi...@ts...>
To: <cpp...@li...>
Sent: Thursday, October 04, 2001 2:57 PM
Subject: [Cppunit-devel] Partial answer: 2.3) Why does the test
ExceptionTest.testAssignment failed in CppUnit test


> The implementation of the assignment operator for std::exception in
> MSVCRT seems to be cause of the problem. Comment out the
> SuperClass::operator= (other) call in Exception::operator=(Exception&)
> and the test now passes.
>
> Examination of MSVCRT disassembly yields some odd-looking (shortcut?)
> behavior. It looks as though exception::operator=(exception&) resets
> itself by calling its own destructor (memory is not freed) then calls
> exception(exception&) to complete the assignment.
>
> I can't progress the problem any further at this time but the
> information above may be of some assistance.
>
> Regards,
> Phil
>
>
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