Re: CString vs std:string

From:
"Ben Voigt [C++ MVP]" <rbv@nospam.nospam>
Newsgroups:
microsoft.public.vc.language
Date:
Mon, 19 Jan 2009 10:54:50 -0600
Message-ID:
<4230F7C9-BAF8-483E-B39F-C3505513A90A@microsoft.com>
"Giovanni Dicanio" <giovanniDOTdicanio@REMOVEMEgmail.com> wrote in message
news:eryJfsCeJHA.4004@TK2MSFTNGP05.phx.gbl...

"Carl Forsman" <fatwallet951@yahoo.com> ha scritto nel messaggio
news:q922n4t8br02615cq3ta2dajf6kb4euaql@4ax.com...

are they basically the same?

except portablity where CString is only microsoft?


No.
They are different...
It's not only portability, it's the public interface, too.

For example:

1) CString plays well with Windows TCHAR model
(instead you should overcome this with STL strings, using something like
typedef std::basic_string< TCHAR > tstring; or something similar...).


Seems pretty similar actually... but the take away message here should be
that std::string plays well with EVERY model because it's templated. This
works both ways -- templates don't work with DLLs, the implementation of
every STL class is compiled into each client directly, so you cannot deploy
security fixes without a recompile. Of course the necessity of inlining to
get reasonable performance suggests that CString suffers from the same
problem even though it isn't templated.

2) CString offers useful methods like Left, Right, etc. to extract
subparts of the string.
Moreover, it offers methods to trim trailing spaces, etc.


Which std::string has also, but with different names.

3) CString is reference counted, instead I believe that std::string is
not.


Perhaps you are referring to Microsoft's std::string implementation in
particular? I think some other Standard C++ Library implementations do
string folding aka reference counting aka copy on write just fine.

4) CString has an implicit operator LPCTSTR such that you can use a
CString whenever an API or something requires an LPCTSTR (const TCHAR *),
instead you must call explicitly call .c_str() method from std::string.


Implicit non-widening conversions are generally considered bad, and
conversion to character pointer (pick your character type, char, wchar_t,
TCHAR) is not widening.

Probably there are other differences also...

If you want to write Windows-only code, you may want to use CString, IMHO
(but I believe that some valuable programmers here would suggest
std::string instead...).

Just my 2 cents,
Giovanni

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