我应该看到std :: bind和boost :: bind之间的显着差异吗？

问题描述

我在g ++的4.7分支上探索对C ++ 11的支持（Ubuntu / Linaro 4.7.3-2ubuntu〜12.04，具体），我似乎发现了差异。特别是，如果我在Boost ASIO异步客户端示例中注释掉boost / bind.hpp的#include并系统地替换boost :: bind与std :: bind的出现（取自），程序不再编译。对此有任何解释吗？

I'm exploring the support for C++11 on the 4.7 branch of g++ (Ubuntu/Linaro 4.7.3-2ubuntu~12.04, to be specific) and I seem to be finding differences. In particular, if I comment out the #include of boost/bind.hpp and systematically replace occurrences of boost::bind with std::bind in the Boost ASIO async client example (taken from http://www.boost.org/doc/libs/1_45_0/doc/html/boost_asio/example/http/client/async_client.cpp), the program no longer compiles. Any explanation for this?

推荐答案

#include <functional>
namespace boost {
    namespace asio {
        namespace stdplaceholders {
            static decltype ( :: std :: placeholders :: _1 ) & error = :: std :: placeholders :: _1;
            static decltype ( :: std :: placeholders :: _2 ) & bytes_transferred = :: std :: placeholders :: _2;
            static decltype ( :: std :: placeholders :: _2 ) & iterator = :: std :: placeholders :: _2;
            static decltype ( :: std :: placeholders :: _2 ) & signal_number = :: std :: placeholders :: _2;
        }
    }
}

并使用 boost :: asio :: stdplaceholders :: * 而不是 boost :: asio :: placeholders :: *

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