error: 'nullptr' was not declared in this scope

nullptr是C++11引入的新特性，解决C和C++中NULL的定义不一致所带来的编译器兼容问题。C中NULL是指向0地址的指针(void *)0，c++中则是定义为整数0.      ndk中解决这个问题的办法就是添加对C++11的支持, 在cmakelists.txt中添加：

include(CheckCXXCompilerFlag)
CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)
CHECK_CXX_COMPILER_FLAG("-std=c++0x" COMPILER_SUPPORTS_CXX0X)
if(COMPILER_SUPPORTS_CXX11)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
elseif(COMPILER_SUPPORTS_CXX0X)
    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++0x")
else()
    message(STATUS "The compiler ${CMAKE_CXX_COMPILER} has no C++11 support. Please use a different C++ compiler.")
endif()