Re: Re: Problem with ostringstream and Daixtrose

Marcus

I have evolved a workaround in which which I put

{ } around the code which needs Daixt::DefaultOps

Then I avoid any operator << to the ostringstream object inside the
{ } and all is well. The object can be passed as an argument inside
the { } code.

Thanks

John

To: [email protected]

From: Markus
Werle <[email protected]>

Subject: [Daixtrose-help]
Re: Problem with ostringstream and Daixtrose

Date sent: Wed,
11 Jan 2006 21:11:07 +0100

> Hi!

>

> Yes, I dislike the way C++ name lookup is unable to be directed

> to the right path here.

> The reason for the error is that

> using namespace Daixt::DefaultOps;

> includes operator<< which is then chosen instead the correct one. I

> should have investigated why this happens even for the case you also

> say

> using namespace std;

>

> Seems like my operator is a better match - which i did not expect.

>

> Unfortuantely Compilers reject

> using std::operator<<;

> and also I would appreciate C++ to have keyword "not"

> not using Daixt::DefaultOps::operator<<

>

> The only way you may get around this problem is by

> using using declaratives (sic!) a la

>

> using Daixt::DefaultOps::operator+;

> using Daixt::DefaultOps::operator-;

> using Daixt::DefaultOps::operator*;

> using Daixt::DefaultOps::operator/;

> using Daixt::DefaultOps::operator==;

> using Daixt::DefaultOps::operator%=;

> using Daixt::DefaultOps::Pow;

> using Daixt::DefaultOps::RationalPow;

>

> instead of using the whole namespace at once.

> Things will get much better in the next evolution step

> of my library, but this issue really bites.

>

> Code snippet that compiles with intel-9 but still fails with

> gcc-3.3.4 which has some trouble with the using stuff, so you

> probably have to take a newer gcc - I am unsure here.

>

> #include "daixtrose/Daixt.h"

> #include "daixtrose/DefaultOps.h"

>

> #include <iostream>

> #include <sstream>

>

> int main()

> {

> using namespace std;

> using Daixt::DefaultOps::operator+;

> //using namespace Daixt::DefaultOps;

>

> std::ostringstream out;

>

>

> //std::cout << "Test of sstream problem " << std::endl;

> out << "Test of sstream problem " << std::endl;

> std::cout << out.str();

> return 0;

> }

>

>

>

> Btw.: I like to see someone else use my lib.

> The key issues become clear in a way I could not

> achieve myself. Thank you for beta-using!

>

> best regards,

>

> Markus

>

--

Dr John P. Fletcher Tel: (44) 121 204 3389 (direct line)

Chemical Engineering and Applied Chemistry (CEAC),

School of Engineering and Applied Science (SEAS),

Aston University, Aston Triangle, BIRMINGHAM B4 7ET U.K.

CEAC Web site http://www.ceac.aston.ac.uk/

FAX: (44) 121 204 3679

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