# Revision history [back]

Thanks for you answer. Can You also point me to the list of functions that interface the msg class? For instance, in JointTestPlugin.cc, some functions are being called _msg.position() and _msg.force(). Where are these functions defined in API?

Also, there is a line in the load function:

this->velSub = this->node->Subscribe(std::string("~/") + this->model->GetName() + "/joint_test_cmd",
&JointTestPlugin::OnJointCmdMsg, this);


I understand that the topic ~/model_name/joint_test_cmd is being subscribed but I don't know where this topic is advertised (perhaps in a separate program?). Where is that program in gazebo folder?

Thanks for you help and sorry for my very long question.