Article ID: 251023
Article Last Modified on 10/2/2003
APPLIES TO
- Microsoft ActiveX Template Library 2.0
- Microsoft ActiveX Template Library 2.1
- Microsoft ActiveX Template Library 3.0
This article was previously published under Q251023
SYMPTOMS
When you assign BSTR to a CComVariant instance using CComVariant::operator=(BSTR), any characters after an embedded NULL character in BSTR are not copied.
CAUSE
This is due to the implementation of CComVariant::operator=(BSTR) not accounting for NULL characters inside BSTR being copied.
RESOLUTION
Instead of using CComVariant::operator=(BSTR) to copy BSTR inside of CComVariant, use the CComVariant::Copy() function and place BSTR inside of VARIANT. The following code snippet could be used to replace CComVariant::operator=(BSTR) if you need to make sure embedded NULL characters and characters after embedded NULL characters are copied.
void Function(BSTR bstrValue)
{
VARIANT v;
v.vt = VT_BSTR;
v.bstrVal = bstrValue;
CComVariant a;
a.Copy(&v); //Use this instead of the next line.
//a = bstrValue; //This would not copy embedded NULLs or chars after NULL.
//Use variant now to do whatever you need.
}
STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.
Additional query words: CComVariant =
Keywords: kbbug kbfix KB251023
