More parentheses are required: (bigCat.*pcat)(); ^ ^ The function call (()) has higher precedence than the pointer-to-member binding operator (.*). The unary operators have higher precedence than the binary operators.
int f(char) { return 0; } int (*return_f())(char) { return f; } No, seriously, use a typedef 🙂
It’s not quite the right question. For C, at least, the right question is What happens to a function value in an rvalue context? (An rvalue context is anywhere a name or other reference appears where it should be used as a value, rather than a location — basically anywhere except on the left-hand side … Read more
funcdict = { ‘mypackage.mymodule.myfunction’: mypackage.mymodule.myfunction, …. } funcdict[myvar](parameter1, parameter2)
It’s a bug in g++. int (*) (int *) is a type name. In C++ you cannot have a declaration with a type name without an identifier. So this compiles with g++. int (*) (int *) = 5; and this compiles as well: int (*) (int *); but they are both invalid declarations. EDIT: T.C. … Read more
This is a simple question but the answer is surprisingly complex. The short answer is you can do what you’re trying to do with std::bind1st or boost::bind. The longer answer is below. The compiler is correct to suggest you use &CLoggersInfra::RedundencyManagerCallBack. First, if RedundencyManagerCallBack is a member function, the function itself doesn’t belong to any … Read more
As far as the C standard is concerned, if you cast a function pointer to a function pointer of a different type and then call that, it is undefined behavior. See Annex J.2 (informative): The behavior is undefined in the following circumstances: A pointer is used to call a function whose type is not compatible … Read more
std::function is a type erasure object. That means it erases the details of how some operations happen, and provides a uniform run time interface to them. For std::function, the primary1 operations are copy/move, destruction, and ‘invocation’ with operator() — the ‘function like call operator’. In less abstruse English, it means that std::function can contain almost … Read more
The syntax is wrong. A member pointer is a different type category from a ordinary pointer. The member pointer will have to be used together with an object of its class: class A { public: int f(); int (A::*x)(); // <- declare by saying what class it is a pointer to }; int A::f() { … Read more
I just ran into this problem. The code compiles fine without lambda captures, but there is a type conversion error with lambda capture. Solution with C++11 is to use std::function (edit: another solution that doesn’t require modifying the function signature is shown after this example). You can also use boost::function (which actually runs significantly faster). … Read more