Re: CComBSTR vs string

From:

"Alex Blekhman" <tkfx.N05P4M@yahoo.com>

Newsgroups:

microsoft.public.vc.language

Date:

Fri, 2 Jun 2006 11:27:56 +0300

Message-ID:

<O5XZ05hhGHA.1244@TK2MSFTNGP04.phx.gbl>

ama wrote:

hi

[using VC6]

I have a function that returns a std::string type.

string getCallFunction(CComBSTR& movie)
{
USES_CONVERSION;
string smovie( W2A(movie) );

string s = "<invoke name=\"flashLoadClip\"
returntype=\"xml\"><arguments>"; s += "<string>";
s += smovie;
s += "</string>";
s += "</arguments></invoke>";

return s;
}

In this sample you don't need std::string at all. CComBSTR
class already has `operator +='. Moreover, converting BSTR
(wide character string) to std::string can result in data
loss if BSTR contains characters which don't exist in
current codepage.

later on i set a CComBSTR ;

string s = getCallFunction( m_movie );
CComBSTR b = s.c_str();

Anyways, while debuging this, the std string contains all
the characters but CComBSTR is cliped and i lose
characters. what's going on ?

First of all, check in debugger settings that "Show Unicode
strings" (or similar wording) is enabled.
Second, as I mentioned before consider to eliminate
std::string at all.

HTH
Alex