Re: Pass CString to printf?

From:
"Mark Salsbery [MVP]" <MarkSalsbery[MVP]@newsgroup.nospam>
Newsgroups:
microsoft.public.vc.mfc
Date:
Thu, 25 Sep 2008 15:44:00 -0700
Message-ID:
<eu3Z4A2HJHA.3496@TK2MSFTNGP05.phx.gbl>
"David Wilkinson" <no-reply@effisols.com> wrote in message
news:Ouq4Oq1HJHA.1156@TK2MSFTNGP04.phx.gbl...

Mark:

I'm not quite sure what your point is here. If it is that you should
always use _tprintf() or CString::Format() rather than printf(), then I
would agree with you.


That was my point yes. The mixing of generic and non generic strings is a
peeve of mine. It's the number one source of string-related bugs IME
looking at people's posted code.

I suppose I should have said nothing.

But suppose you do use printf(). In a Unicode build I can see that you
will not get the answer you expect, but what is the difference between
using the LPCTSTR cast or not?


I didn't say there was a difference (I don't think).

Jonathan Wood stated using the cast is more efficient, but I just looked at
the disassembly of my test code (below) and it seems NOT using the cast is
the most efficient. I could be wrong :)

//
// Test platform: VS 2008 SP1 on Vista Ultimate
//
// Unicode build!
//
CString kindOfFruit = _T("bananas");
int howmany = 25;
char bufff[250];
sprintf(bufff, "You have %d %s", howmany, kindOfFruit);
sprintf(bufff, "You have %d %s", howmany, (LPCTSTR)kindOfFruit );
sprintf(bufff, "You have %d %s", howmany,
static_cast<LPCTSTR>(kindOfFruit));
sprintf(bufff, "You have %d %s", howmany, CT2A(kindOfFruit) );

Mark

--
Mark Salsbery
Microsoft MVP - Visual C++

--
David Wilkinson
Visual C++ MVP

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