Re: _CrtIsValidHeapPointer problem while exporting dll vc6.

I am using Microsoft VC++6. I am facing a problem while
exporting a dll
which uses the std::string, in to an exe. both the dll and
the exe are
complied as 'debug multi threaded' option.

         I will list the code, of both the dll and the exe
and will
give the description of the probelm.
There is a class named 'Field' in the dll.

//////////////////////Start of
src//////////////////////////////
Field.h
-----------

class Field
{
private:
string m_sValue;

public:
LIBSPEC Field ();
LIBSPEC void sGetValue (const char*& szValue);
LIBSPEC void setValue (const char *sName);
~Field ()
{

}
#undef LIBSPEC
};
/////////////////////////////////////////////////////////////////////////////////////////////

Field.cpp
-------------

Field::Field ()
{
}

void Field::sGetValue (const char*& szValue)
{
szValue = m_sValue.c_str();//break_string (m_sValue.begin
(),
m_sValue.end ());
}

void Field::setValue (const char* szValue)
{
m_sValue = szValue;//szValue;
}

/////////////////////////////////////////////////////////////////////////////////

main.cpp
-------------

main()
       Field *fdl = new Field;
const char* str1 ="TESTFIELD";
fdl->setValue (str1);
delete fdl;

//////////////////////////////End of
src////////////////////////////////////

In the main (), i am creating an object of the class
'Field'. I am
setting the value in the object by calling the
Field::setValue member.
                  the problem occurs, when the object is
'delete'd.
the debug assertion is failed in the
_CrtIsValidHeapPointer (). when i
tried tracing, the control goes into the destructor, and
at the end of
the destructor this error is occured.

                    as per my knowledge, the dynamically
allocated
memory should be freed in the same module in which it is
created.
                      as i understood, the string
'm_sValue' in the
Field is allocated in the dll's heap by the
Field::setValue () and in
its destructor the same memory is freed. so, as the
destructor should
be asserting using the dll's heap there should not be any
problem.
                                  is it possible that the
assertion in
the destructor is done with the application's heap which
results in the
error as it is allocated in the dll's heap?