Oliver Kowalke <oliver.kowalke@t-online.de> wrote:
Hi,
I want to use boost::shared_ptr with boost::signal.
class A { private: int _i; public: A() : _i( 0) {}
void operator()( int, std::string & s) { i+= 1; }
void operator()( std::string & s, int) { i+= 2; } };
boost::shared_ptr< A > a( new A() ); boost::signal< void( int, std::string &) > rsig; boost::singal< void( std::string &, int) > lsig;
rsig.connect( a); lsig.connect( a);
rsig(0,"called from right side"); lsig("called from left side",0);
Because a is a smart_ptr this code would not compile because operator() is not a member function. If I dereference the smart pointer when I connect to signal, changes of a are never know by the other signal instance. Maybe I can use a proxy class which aggregates the smart pointer but maybe there is a better solution?!
As a general rule, functors are expected to be copiable and not to have mutable state of their own. So how about putting the shared_ptr inside A instead: class A { private: boost::shared_ptr<int> _i; public: A() : _i(new int(0)) {} void operator()(int, std::string & s) { *_i += 1; } void operator()(std::string & s, int) { *_i += 2; } }; A a;