boost-bind

I'm trying to reference a member of a (yet) unknown instance from within a boost::spirit rule definitions' action, so in pseudocode, instead of double_[ref(rN) = _1] I'm looking for something like X** ppx; double_[ref(&X::rN, ppx) = _1] A workaround for it could be a simple "semantic action" with a parameter which knows the instance and would be able to write to it, like qi::rule<Iterator, Skipper> start; my_grammar(DataContext*& dataContext) : my_grammar::base_type(start) , execContext(execContext) { start = qi::double_[ boost::bind(&my_grammar::newValueForXY, dataContext, ::_1) ]; However, I

I have an object type like this: struct T { int x; bool y; }; and a container of them like this: std::vector<T> v; and a burning desire to determine — in a single statement — whether any of the elements of v have y == true . This likely involves std::find_if . My understanding is that std::bind and boost::bind are for member functions and cannot be applied to member data. Because I dislike them, I wish to avoid: comparison functions/functors loops Because my environment is C++03, the following are not available: lambdas Lightness Races with Monica My understanding is that std::bind and boost:

I have a std::vector<std::string> temp_results and I wish to use std::for_each to go through this vector and concatenate a string, so I concocted the following construction: std::stringstream ss; std::string res = std::for_each(temp_results.begin(), temp_results.end(), boost::bind(addup, _1, ss)); std::string addup(std::string str, std::stringstream ss) { ss << str; ss << ";"; return ss.str; } I get the following error, which is beyond my understanding: error C2475: 'std::basic_stringstream<_Elem,_Traits,_Alloc>::str' : forming a pointer-to-member requires explicit use of the address-of

If I were to wanted to parameterize creating an object, I could of course make a function which called new on a particular class and passed out a pointer. I am wondering if it's possible to skip that step and pass a function pointer to the new operator itself. boost::lambda provides function wrappers for new and delete . These can be used to easily convert an new call into a function object. operator new (as well as the other flavours) takes care of allocating memory but does not construct objects. In fact its return type is void* . What constructs an object is a new expression , which is part

Are there any performance impacts (positive or negative) when binding functions (using Boost Bind) ? Maybe, may not be. It depends. The result of std::bind (or also boost::bind ) is a so-called "bind expression", which has an un­know­able type determined by the implementation. This type is a Callable , and it is convertible to an in­stance of std::function (or boost::function ). Internally, function (may) use type erasure to handle various complex, stateful "call­able objects". This entails a dynamic allocation and a virtual dispatch in some (though not neces­sari­ly all) cases. Both bind and

I have a one-dimensional function minimizer. Right now I'm passing it function pointers. However many functions have multiple parameters, some of which are held fixed. I have implemented this using functors like so template <class T> minimize(T &f) { } Functor f(param1, param2); minimize<Functor>(f); However the functor definition has lots of crud. Boost::bind looks cleaner. So that I could do: minimize(boost:bind(f,_1,param1,param2)) However I'm not clear what my minimize declaration should like like using boost::bind . What type of object is boost::bind ? Is there an easy pattern for this

We're getting this compile error followed by many more errors showing attempts to match the subscribe parameters to all possible candidate functions when using boost::bind as a callback for subscribe. error: no matching function for call to ‘ros::NodeHandle::subscribe(const char [18], int, boost::_bi::bind_t<void, void (*)(const geometry_msgs::WrenchStamped_<std::allocator<void> >&, moveit::planning_interface::MoveGroup&), boost::_bi::list2<boost::arg<1>, boost::_bi::value<moveit::planning_interface::MoveGroup*> > >)’ Our code is as follows. The commented lines show the code which works when