c++ - boost::bind & boost::function with partial args

Question

我给你发了一个我想做的例子，用这种方式更容易解释

    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
     }

有什么想法吗？

Answer 1

跳过那个参数。

   boost::function<void(int my_number)> functionWithSavedArgs
        = boost::bind(&myPrinter, someText);

这只绑定(bind)第一个参数。

如果你只想绑定(bind)第二个，你需要一个占位符:

   boost::function<void(int my_number)> functionWithSavedArgs
         = boost::bind(&myPrinter, _1, someNumber);