function-pointers

问题 I have the following class in Python that I am trying to use for calling a set of its own methods through a dictionary that has the pointers of the available functions: class Test(): functions = { 'operation_a' : Test.function_a; 'operation_b' : Test.function_b; } def run_operations(operation, *args, **kwargs): try: functions[str(operation)](self, args, kwargs) except KeyError: // some log ... def function_a(self, *args, **kwargs): print A def function_b(self, *args, **kwargs): print B This

问题 In my code, a vtable containts several function pointer. Doxygen is unable to follow them. I'd like to force it to recognize the possible paths, to produce a complete Call Graph, since now this part is missing. example: typedef Bool(*SPECIAL_FUNC)(KEY key); typedef struct{ int a; int b; SPECIAL_FUNC; }OBJ; Bool add(KEY key); //code... Bool sub(KEY key); //code... 回答1: While this will likely not affect the call graph in doxygen, you can document the functions as related to the structure, and

问题 This is similar to another question I've asked, but, I've created an expression class that works like so: expression<int, int> exp(10, 11, GreaterThan); //expression<typename T, typename U> exp(T val1, U val2, oper op); //where oper is a pointer to bool function(T, U) where GreaterThan is a previously defined function. And I am wondering why I can't do this: expression<int, int> exp(10, 11, >); particularily when > is overloaded as bool operator>(int a, int a){return (a > b);} which is

问题 This is a follow up on How do I get the argument types of a function pointer in a variadic template class? I have this struct to access the arguments of a variadic template: template<typename T> struct function_traits; template<typename R, typename ...Args> struct function_traits<std::function<R(Args...)>> { static const size_t nargs = sizeof...(Args); typedef R result_type; template <size_t i> struct arg { typedef typename std::tuple_element<i, std::tuple<Args...>>::type type; }; }; And I

问题 I'm injecting a DLL into another process and want to call a function that is in that binary based on it's address (0x54315). How can I actually declare a function, and then set it to this address? #define FUNC 0x54315 void *myFuncPtr; int main() { myFuncPtr = FUNC; // pretty sure this isn't how myFuncPtr(); // call it? } 回答1: The existing answers work, but you don't even need a variable for the function pointer. You can just do: #define myfunc ((void (*)(void))0x54315) and then call it as

问题 Suppose we have this code: template <class T, void (*u)(T&)> void Foo() { // store the function u internally . . . } There are reasons to do something like this and I won't attempt to go into them. However, is there any way to avoid having to specify type T when calling Foo() ? For example, to compile, one normally needs: Foo<int, MyIntFunction>(); But if this int can be deduced from the function pointer, is this possible: Foo<MyIntFunction>(); EDIT I'm aware of the solution to pass the

问题 In C you can put function pointers into an array of void pointers and convert them back to function pointers of any type: extern int (*fn1)(void); extern void (*fn2)(int); void foo(void) { void *array[2]; int i; /* implicit cast from function pointer to void pointer */ array[0] = fn1; array[1] = fn2; for (i = 0; i < 2; i++) { int (*fp)(int, int, int); /* implicit cast from void pointer to function pointer */ fp = array[i]; /* call function with a different signature */ fp(1, 2, 3); } } I need

问题 In the code: #include <tbb/tbb.h> int GetSomething() { int something; // do something return something; } // ... tbb::tbb_thread(GetSomething, NULL); // ... Here GetSomething() was called in another thread via its pointer. But can we get return value from GetSomething() ? How? 回答1: If you are bound C++03 and tbb you have to use Outputarguments, which means that you have to rewrite your function. e.g.: void GetSomething(int* out_ptr); int var = 23; tbb::tbb:thread(GetSomething, &var); // pay

问题 I am currently in the process of writing a method execution queue in C++x0. I have implemented and verified the basic queue mechanism but want to amend it with an option to have push() automatically remove all previous calls to a specific method: queue.push(this, &Obj::foo, 1); queue.push(this, &Obj::foo, 2); queue.push(this, &Obj::foo, 3); should be the same as merely calling queue.push(this, &Obj::foo, 3); My code thus far looks like this: Queue.h: #pragma once #include <functional>

问题 I am defining function pointer inside a class and trying to access it through an instance of the class but it shows an error. Here is the code: 1 #include<stdio.h> 2 3 class pointer { 4 public: 5 int (pointer::*funcPtr)(int); 6 pointer() { 7 funcPtr = &pointer::check; 8 } 9 10 11 int check(int a) 12 { 13 return 0; 14 } 15 16 }; 17 18 int main() 19 { 20 pointer *pt=new pointer; 21 return (pt->*funcPtr)(3); 22 } It shows a compile time error: checkPointer.cpp:21:15: error: ‘funcPtr’ was not