error: ‘shared_ptr’ in namespace ‘std’ does not name a type

用G++编译项目的时候发生标题上的错误，原因是，这是c++ 11标准的。在给g++传递命令行的时候加上-std=c++0x就行了。

还需要在源码中#include<memory>

我的cmakelists里面要这样改：

   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}  -std=c++0x")

references:

http://www.cmake.org/Wiki/CMake/Tutorials/C%2B%2B11Flags

http://stackoverflow.com/questions/12329226/a-short-c-file-and-makefile-i-can-make-in-the-shell-but-get-lots-of-error-wh

https://github.com/RobotLocomotion/drake/issues/92