I'm running into a bit of a problem here, I'm messing around with machine code and function pointers, and there's a bit of my code that VC++ simply refuses to compile. This compiles and runs exactly as expected: #include <stdlib.h> #include <stdio.h> int main() { char tarr[] = {0xb8, 222, 0, 0, 0, 0xc3}; int (*testfn)() = tar...
Given the following code which I can't get to compile. template < typename OT, typename KT, KT (OT::* KM)() const > class X { public: KT mfn( const OT & obj ) { return obj.*(KM)(); // Error here. } }; class O { public: int func() const { ...
typedef void int_void(int); int_void is a function taking an integer and returning nothing. My question is: can it be used "alone", without a pointer? That is, is it possible to use it as simply int_void and not int_void*? typedef void int_void(int); int_void test; This code compiles. But can test be somehow used or assigned to som...
In c++, when and how to use a callback function? EDIT: I would like to see a simple example to write a callback function. ...
The following code gives an compilation error for void b() { m = &A::a; }; stating that A::a() is protected. (Which it is - but that should be no problem) However the compiler doesn't care when I write B::a(). Even though both mean the same I would prefer A::a() because it states explicitely that a() is defined in A. So what is the reas...
I am inspecting a piece of existing code and found out it behaves differently when compiled with Visual C++ 9 and MinGW: inline LogMsg& LogMsg::operator<<(std::ostream& (*p_manip)(std::ostream&) ) { if ( p_manip == static_cast< std::ostream& (*)(std::ostream&) > ( &std::endl<char, std::char_traits<char> >) ) { msg(m_outp...
Consider this javascript code: var bar = function () { alert("A"); } var foo = bar; bar = function () { alert("B"); }; foo(); When running this code I get "A". Is this behavior a part of javascript specification and can I rely on it? ...
Hello, in C++, I can easily create a function pointer by taking the address of a member function. However, is it possible to change the address of that local function? I.e. say I have funcA() and funcB() in the same class, defined differently. I'm looking to change the address of funcA() to that of funcB(), such that at run time callin...
I have a problem with using a pointer to function in C++. Here is my example: #include <iostream> using namespace std; class bar { public: void (*funcP)(); }; class foo { public: bar myBar; void hello(){cout << "hello" << endl;}; }; void byebye() { cout << "bye" << endl; } int main() { foo testFoo; testFoo...
I had this problem some time ago and I gave up but lately it returned. #include <iostream> class element2D; class node2D { public: void (element2D::*FunctionPtr)(); void otherMethod() { std::cout << "hello" << std::endl; ((this)->*(this->FunctionPtr))(); //ERROR<------------------- } }; class element2D { publ...
I came across the following weird chunk of code.Imagine you have the following typedef: typedef int (*MyFunctionPointer)(int param_1, int param_2); And then , in a function , we are trying to run a function from a DLL in the following way: LPCWSTR DllFileName; //Path to the dll stored here LPCSTR _FunctionName; // (mangled) name...
I am working on a transliteration tool. I have two modules lexer and translator. Lexer generates tokens out of the input text. Depending on the current language chosen, I have to call appropriate translation routine. I have came up with couple of ideas to do this. First one is to create a base class something called base_translator and ...
I'd like to set up a function pointer as a member of a class that is a pointer to another function in the same class. The reasons why I'm doing this are complicated. In this example, I would like the output to be "1" class A { public: int f(); int (*x)(); } int A::f() { return 1; } int main() { A a; a.x = a.f; printf("%d\n",a....
This one is quite obviously a function pointer : typedef int (* foobar) (int a, unsigned char *b, unsigned int c); But what does this one do? typedef int (foobar *) (int a, unsigned char *b, unsigned int c); ...
Hi guys. I read about function pointers in C. And everyone said that will make my program run slow. Is it true? I made a program to check it. And I got the same results on both cases. (measure the time.) So, is it bad to use function pointer? Thanks in advance. To response for some guys. I said 'run slow' for the time that I have comp...
I have a function which takes a block of data and the size of the block and a function pointer as argument. Then it iterates over the data and performes a calculation on each element of the data block. The following is the essential outline of what I am doing: int myfunction(int* data, int size, int (*functionAsPointer)(int)){ //wa...
I have got a problem with calling a global function, which takes a pointer to a function as a parameter. Here is the declaration of the global function: int lmdif ( minpack_func_mn fcn, void *p, int m, int n, double *x, double *fvec, double ftol) The "minpack_func_mn" symbol is a typedef for a pointer to a function, defin...
Hi all, I need an array to hold member-function-pointers of different classes. How can I define the array? The code should look like this : arr[0] = &CMyClass::FuncX; arr[1] = &CYourClass::FuncY; arr[2] = &CHerClass::FuncZ; I tried void*, but it doesn't work. Thanks. Best regards, Zach@Shine ...
Is it possible to call a c(++) static function pointer (not a delegate) like this typedef int (*MyCppFunc)(void* SomeObject); from c#? void CallFromCSharp(MyCppFunc funcptr, IntPtr param) { funcptr(param); } I need to be able to callback from c# into some old c++ classes. C++ is managed, but the classes are not ref classes (yet)....
I want to pass a member function of class A to class B via a function pointer as argument. Please advise whether this road is leading somewhere and help me fill the pothole. #include <iostream> using namespace std; class A{ public: int dosomeA(int x){ cout<< "doing some A to "<<x <<endl; return(0); } }; class B{ public: B...