现象

如题，在运行ns3-gym的时候想加入anim，图文并茂，但常规地加入头文件和声明报错如下：

~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:913:(.text.unlikely+0x1377): undefined reference to `ns3::AnimationInterface::~AnimationInterface()'
/usr/bin/ld: CMakeFiles/linear-mesh.dir/linear-mesh/sim.cc.o: in function `main':
~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:888:(.text.startup+0x4b7d): undefined reference to `ns3::AnimationInterface::AnimationInterface(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
/usr/bin/ld: ~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:895:(.text.startup+0x4be9): undefined reference to `ns3::AnimationInterface::UpdateNodeColor(ns3::Ptr<ns3::Node>, unsigned char, unsigned char, unsigned char)'
/usr/bin/ld: ~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:894:(.text.startup+0x4c4b): undefined reference to `ns3::AnimationInterface::UpdateNodeDescription(ns3::Ptr<ns3::Node>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
/usr/bin/ld: ~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:897:(.text.startup+0x4cab): undefined reference to `ns3::AnimationInterface::UpdateNodeDescription(ns3::Ptr<ns3::Node>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
/usr/bin/ld: ~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:898:(.text.startup+0x4cf1): undefined reference to `ns3::AnimationInterface::UpdateNodeColor(ns3::Ptr<ns3::Node>, unsigned char, unsigned char, unsigned char)'
/usr/bin/ld: ~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:901:(.text.startup+0x4d37): undefined reference to `ns3::AnimationInterface::UpdateNodeDescription(ns3::Ptr<ns3::Node>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
/usr/bin/ld: ~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:902:(.text.startup+0x4d7a): undefined reference to `ns3::AnimationInterface::UpdateNodeColor(ns3::Ptr<ns3::Node>, unsigned char, unsigned char, unsigned char)'
/usr/bin/ld: ~/ns-3.40/contrib/opengym/examples/linear-mesh/sim.cc:913:(.text.startup+0x4df2): undefined reference to `ns3::AnimationInterface::~AnimationInterface()'

头文件和声明：

#include "ns3/netanim-module.h"
AnimationInterface anim("complex-bridge.xml");

事实上之前scratch里面跑的cc从来没有这种问题，以上内容就足够

排错

报错是“/usr/bin/ld”报错，所以是链接问题，所以大概是没有库，所以去看CMakelists：

build_lib_example(
  NAME linear-mesh
  SOURCE_FILES linear-mesh/sim.cc
  LIBRARIES_TO_LINK
    ${libapplications}
    ${libcore}
    ${libinternet}
    ${libopengym}
    ${libwifi}
)

查看anim有关CMakelists：

build_lib_example(
  NAME wireless-animation
  SOURCE_FILES wireless-animation.cc
  LIBRARIES_TO_LINK
    ${libnetanim}
    ${libapplications}
    ${libpoint-to-point}
    ${libcsma}
    ${libwifi}
    ${libmobility}
    ${libnetwork}
)

缺少    ${libnetanim}，加上就好了。