How to avoid shared_ptr ambiguity? (stl vs boost)

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Why is ‘using namespace std;’ considered a bad practice in C++?

I've used stl's shared_ptr many places in my code and I have used the following using statement anywhere that I have used shared_ptr:

using namespace std::tr1;

Now I need to use boost::bimap. So I have to include the following header file in my code:

#include <boost/bimap.hpp>

As soon as I include the bimap header file, the shared_ptr type becomes ambiguous, and I have to change all usages of shared_ptr to std::tr1::shared_ptr. Since this makes my code ugly, I am looking for a way to avoid this ambiguity without needing to declare shared_ptr everywhere with a fully qualified name. I was thinking of using typedef for std::tr1::shared_ptr, but maybe there are better ways too. Any advice would be appreciated!

And we finally see why `using` directives are a scourge upon the nation. Just. Say. No. — Kerrek SB, Dec 09 '12 at 12:49

score 6 · Accepted Answer · answered Dec 09 '12 at 12:48

6

simply do not introduce it. avoid the general using namespace ...

answered Dec 09 '12 at 12:48

stefan

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Some programmer dude · Answer 2 · 2012-12-09T13:03:21.660

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How about the following:

using shared_ptr = std::tr1::shared_ptr;

However, the correct answer would actual be to not use the using namespace ... statement, or only use it to create namespace aliases.

By the way, you know that std::tr1 is obselete since C++11 became standardised last year?

edited Dec 09 '12 at 13:03

answered Dec 09 '12 at 12:49

Some programmer dude

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I know but due to some limitations, I cannot switch to C++11 yet. – B Faley Dec 09 '12 at 12:53
and the above `using` does not work: `error: expected nested-name-specifier before ‘share_ptr’` `error: expected ‘;’ before ‘=’ token` – B Faley Dec 09 '12 at 12:58
@Meysam What compiler and what version of it are you using? It may be that it doesn't support the new type aliases yet. – Some programmer dude Dec 09 '12 at 12:59
g++ (Ubuntu/Linaro 4.6.1-9ubuntu3) 4.6.1 – B Faley Dec 09 '12 at 12:59
@FredOverflow Hrm... share or shared... does it really matter? ;) – Some programmer dude Dec 09 '12 at 13:04
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Template aliases are not supported until g++ 4.7 IIRC. – fredoverflow Dec 09 '12 at 13:10
This won't work in most compilers – Dmitri Nesteruk Mar 13 '14 at 11:26

How to avoid shared_ptr ambiguity? (stl vs boost)

2 Answers2