Error C2280 mutex in a class C++ -

i'm having issue declaring mutex in class, whenever attempt instantiate class error c2280 appears. project create simulation of dining philosopher's problem.

declaration:

class fork {  public:  struct _position {     float x;     float y; };  fork(); fork(int num_phil_, int new_index_); _position returnworkposition(){ _position return_position_; /*position_mutex_.lock();*/ return_position_ = work_position_;                                      /*position_mutex_.unlock();*/ return return_position_; }; float returnrotation(){ return rotation_; };  void calculateworkposition(int master_index_); void resetworkposition(){ /*position_mutex_.lock();*/ work_position_ = orig_position_; /*position_mutex_.unlock();*/ }; void takeownership(int master_index_); void relinquishownership();  private:  int index_; int num_philosophers_; float rotation_;  _position orig_position_; _position work_position_;  //std::mutex master_mutex_; //std::mutex position_mutex_; }; 

instantiation:

for (int = 0; < num_philosophers_; i++) {     fork temp_fork_(num_philosophers_, i);     fork_.push_back(temp_fork_); } 

edit:: new declaration:

class fork {  public:  fork(); fork(int num_phil_, int new_index_);  fork(fork const&) = delete; fork& operator=(fork const&) = delete;  struct _position {     float x;     float y; };  _position returnworkposition(){ _position return_position_; /*position_mutex_.lock();*/ return_position_ = work_position_;                                      /*position_mutex_.unlock();*/ return return_position_; }; float returnrotation(){ return rotation_; };  void calculateworkposition(int master_index_); void resetworkposition(){ /*position_mutex_.lock();*/ work_position_ = orig_position_; /*position_mutex_.unlock();*/ }; void takeownership(int master_index_); void relinquishownership();  private:  int index_; int num_philosophers_; float rotation_;  _position orig_position_; _position work_position_;  //std::mutex master_mutex_; //std::mutex position_mutex_; }; 

error messages:

error   18  error c2280: 'fork &fork::operator =(const fork &)' : attempting reference deleted function    c:\program files (x86)\microsoft visual studio 12.0\vc\include\xutility 2045    1   lab3e  error   13  error c2280: 'fork::fork(const fork &)' : attempting reference deleted function    c:\program files (x86)\microsoft visual studio 12.0\vc\include\xmemory0 600 1   lab3e 

new instantiation:

for (int = 0; < num_philosophers_; i++) {     fork temp_fork_(num_philosophers_, i);     fork_.emplace_back(temp_fork_); } 

you need delete copy constructor , copy-assignment operator. cannot copy std::mutex , therefore cannot copy instance of class, can construct or move one.

fork(fork const&) = delete; fork& operator=(fork const&) = delete; 

the error telling you trying reference deleted function, copy constructor, because push_back trying copy temp_fork_. instead, use emplace_back create fork in-place.

for (int = 0; < num_philosophers_; i++) {     fork_.emplace_back(num_philosophers_, i); } 

or

for (int = 0; < num_philosophers_; i++) {     fork temp_fork_(num_philosophers_, i);     fork_.push_back(std::move(temp_fork_)); } 

side note
instead of manually locking , unlocking std::mutex, can using std::lock_guard, class set handle locking/unlocking mutex via raii

void resetworkposition() {     std::lock_guard<std::mutex> lock(position_mutex_);  // position_mutex_ locked     work_position_ = orig_position_; };  // lock fell out of scope, position_mutex_ unlocked  _position returnworkposition() {     _position return_position_;     std::lock_guard<std::mutex> lock(position_mutex_);  // position_mutex_ locked     return_position_ = work_position_;     return return_position_; };