的std :: make_pair与C ++ 11 [英] std::make_pair with c++ 11
问题描述
您好,我有以下code:
Hello I have the following code:
bool PinManager::insertPin(const std::string& p_pinNumber, const std::string& p_mode)
{
boost::shared_ptr<GPIOPin> pin(new GPIOPin(p_pinNumber, p_mode));
if (pin)
{
m_pinsInUse.insert(std::make_pair<std::string, boost::shared_ptr<GPIOPin> >(p_pinNumber, pin));
return true;
}
return false;
}
这code一直编译,但是当我添加了 -std =的C ++ 0x
将此code失败,该消息编译:
This code has always compiled, but when I added the -std=c++0x
flag this code fails to compile with the message:
[ 42%] Building CXX object gpioaccess/CMakeFiles/gpioaccess.dir/pinmanager/pinmanager.cpp.o
/home/pi/robot_2.0/trunk/gpioaccess/pinmanager/pinmanager.cpp: In member function 'bool gpioaccess::PinManager::insertPin(const string&, const string&)':
/home/pi/robot_2.0/trunk/gpioaccess/pinmanager/pinmanager.cpp:39:101: error: no matching function for call to 'make_pair(const string&, boost::shared_ptr<gpioaccess::GPIOPin>&)'
/home/pi/robot_2.0/trunk/gpioaccess/pinmanager/pinmanager.cpp:39:101: note: candidate is:
/usr/include/c++/4.6/bits/stl_pair.h:262:5: note: template<class _T1, class _T2> std::pair<typename std::__decay_and_strip<_T1>::__type, typename std::__decay_and_strip<_T2>::__type> std::make_pair(_T1&&, _T2&&)
gpioaccess/CMakeFiles/gpioaccess.dir/build.make:77: recipe for target 'gpioaccess/CMakeFiles/gpioaccess.dir/pinmanager/pinmanager.cpp.o' failed
make[2]: *** [gpioaccess/CMakeFiles/gpioaccess.dir/pinmanager/pinmanager.cpp.o] Error 1
CMakeFiles/Makefile2:75: recipe for target 'gpioaccess/CMakeFiles/gpioaccess.dir/all' failed
make[1]: *** [gpioaccess/CMakeFiles/gpioaccess.dir/all] Error 2
Makefile:75: recipe for target 'all' failed
make: *** [all] Error 2
做一个小挖之后,我发现,在此之前编制的事实,可能是一个错误;但是,我仍然不确定如何解决这个问题。有没有人有正确的方向的点?
After doing a little digging I found that the fact this compiled before was probably a bug; however, I am still unsure how to fix this. Does anyone have any points in the correct direction?
的gcc --version
是海湾合作委员会(Debian的4.6.3-14 + rpi1)4.6.3
推荐答案
的std :: make_pair </ code>
定义,C ++ 03和C ++ 11之间变化。在C ++ 11它需要的参数的通过转发引用的而不是通过值的。这意味着,通过明确指定其类型模板参数你结束了以下实例:
The std::make_pair
definition has changed between C++03 and C++11. In C++11 it takes arguments by forwarding-references rather than by value. This means that by specifying its type template arguments explicitly you end up with the following instantiation:
std::make_pair<std::string , boost::shared_ptr<GPIOPin> >
(std::string&&, boost::shared_ptr<GPIOPin>&&);
期待的右值的参考,不能结合您在通过左值。
expecting rvalue references, which cannot bind to lvalues that you pass in.
您不应该传递类型模板参数的std :: make_pair </ code>明确,并让编译器推断出他们自身的:
You should not pass type template arguments to std::make_pair
explicitly, and let the compiler deduce them on its own:
std::make_pair(p_pinNumber, pin)
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