error: 'nullptr' was not declared in this scope

nullptr是C++11引入的新特性，解決C和C++中NULL的定義不一致所帶來的編譯器兼容問題。C中NULL是指向0地址的指針(void *)0，c++中則是定義爲整數0.      ndk中解決這個問題的辦法就是添加對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()