Actually I don't want to copy a mutex. I just want my class that has a mutex to be copyable, without having to write a copy ctor and operator= (that copy everything except the mutex). Using this class solves the problem for me, but I have a feeling it is not safe to do this. class recursive_mutex_ignorecopy : public boost::recursive_mutex { public: recursive_mutex_ignorecopy() : boost::recursive_mutex() {} ~recursive_mutex_ignorecopy() {} recursive_mutex_ignorecopy(const recursive_mutex_ignorecopy&) {} recursive_mutex_ignorecopy& operator=(const recursive_mutex_ignorecopy&) {} }; Is this a good solution that could maybe be made part of boost, in such a way that it is guaranteed to work and be safe? Or is there a better solution? Thanks, Phillip Hellewell P.S. Perhaps this is a moot point, sinceI just realized that for thread-safety I really need to write my own copy ctor and operator= anyways, that will be synchronized with my other functions that initialize shared pointers and stuff. And I need to lock the rhs's mutex too...