How can I receive a message in actionlib without using a non-const ptr? I checked the headers for SimpleActionServer and it seems like it can only accept a const-ptr as argument in the callback function and indeed the code does not compile when the type isn't const. Is there a way to get a non-const-ptr as argument? If, not, how do I properly convert a const-ptr to non-const ptr - http://answers.ros.org/question/255353/convert-message-const-ptr-to-non-const-ptr/