boost-bind

问题 I can see that there are two different bind libraries for Boost, one "standalone", that can be used by including boost/bind.hpp , and another by including boost/lambda/bind.hpp . What's the difference between these two? 回答1: Have a look at the explanation here: http://boost.org/doc/libs/1_46_0/doc/html/lambda/s08.html#id2143701 They have overlapping functionality but with semantic differences, they can't be used interleaved. 来源： https://stackoverflow.com/questions/5202974/what-is-the

问题 Is there a way to partially bind the first/last n arguments of a callable object (e.g. function) without explicitly specifying the rest of the arguments? std::bind() seems to require that all the arguments are be bound, those that are to be left should be bound to std::placeholders::_1 , _2 , _3 etc. Is it possible to write a bind_first() / bind_last() for partial binding starting from the first/last argument and that automagically inserts the placeholders for any remaining unbound arguments

问题 Please have a look at this example posted by Johannes Schaub to sort a vector of pairs: How do I sort a vector of pairs based on the second element of the pair? std::sort(a.begin(), a.end(), boost::bind(&std::pair<int, int>::second, _1) < boost::bind(&std::pair<int, int>::second, _2)); I thought I do understand boost::bind, but I have trouble with this one. Question 1: the sort algorithm is expecting a predicate function as a third parameter. What I see here, is a boolean expression. What am

问题 I wrote some code and got scared that it will not work - so I wrote a prototype: #include <boost/function.hpp> #include <boost/bind.hpp> #include <iostream> class base { private: boost::function<void (int)> action; protected: virtual void onDataBaseReady(int i) { std::cout << i << std::endl; } public: void call() { action(10); } base() { action = boost::bind(&base::onDataBaseReady, this, _1); } }; class child : public base { protected: virtual void onDataBaseReady(int i) { std::cout << i+10 <

问题 I wrote some code and got scared that it will not work - so I wrote a prototype: #include <boost/function.hpp> #include <boost/bind.hpp> #include <iostream> class base { private: boost::function<void (int)> action; protected: virtual void onDataBaseReady(int i) { std::cout << i << std::endl; } public: void call() { action(10); } base() { action = boost::bind(&base::onDataBaseReady, this, _1); } }; class child : public base { protected: virtual void onDataBaseReady(int i) { std::cout << i+10 <

问题 Forgive my ignorance in asking this basic question but I've become so used to using Python where this sort of thing is trivial that I've completely forgotten how I would attempt this in C++. I want to be able to pass a callback to a function that performs a slow process in the background, and have it called later when the process is complete. This callback could be a free function, a static function, or a member function. I'd also like to be able to inject some arbitrary arguments in there

问题 I've always believed that function pointers don't require an ampersand: Do function pointers need an ampersand Yet, every example I've seen of using boost::bind shows one, and my compiler - in most situations - gives a typically inscrutable error message if it's omitted. synchronize(boost::bind(&Device::asyncUpdate , this, "ErrorMessage")); // Works synchronize(boost::bind(Device::asyncUpdate , this, "ErrorMessage")); // Fails Am I wrong in assuming that boost::bind 's first parameter is

问题 Without spending a long time reviewing the boost source code, could someone give me a quick rundown of how boost bind is implemented? 回答1: I like this piece of the bind source: template<class R, class F, class L> class bind_t { public: typedef bind_t this_type; bind_t(F f, L const & l): f_(f), l_(l) {} #define BOOST_BIND_RETURN return #include <boost/bind/bind_template.hpp> #undef BOOST_BIND_RETURN }; Tells you almost all you need to know, really. The bind_template header expands to a list of

问题 Why does valgrind's DRD tool complaines "Conflicting load by thread ... at size 4": about such code: void SomeFunction(const int& value) { boost::bind(..., value); /* <-- complaines on this line with last backtrace function "new(int)" */ } Does boost::bind() stores values by reference or value? 回答1: By value. 1 But you can make it copy by ref instead: void SomeFunction(const int& value) { boost::bind(..., boost::ref(value)); boost::bind(..., boost::cref(value)); // by const ref } 1 http://www

问题 I post you an example of what I want to do, that is easier to explain in this way void myPrinter(const char* text, int number){ printf("\n%s %d\n", text, number); } int main() { char *someText="test"; boost::function<void(int my_number)> functionWithSavedArgs = boost::bind(&myPrinter, someText, ?????); //then I have to call my function with saved args and give to it only variable "number" like: int myBeautifulNumber = 2012; functionWithSavedArgs(myBeautifulNumber); // echo: test 2012 } Any