function-pointers

I'm using an API that requires me to pass a function pointer as a callback. I'm trying to use this API from my class in C++ but I'm getting compilation errors. The API definition is: typedef void (__stdcall *STREAM_CALLBACK)(void *userdata); __declspec(dllimport) int __stdcall set_stream_callback( STREAM_CALLBACK streamCB, void *userdata); One example file, provided by the third party, is: void __stdcall streamCB(void *userdata) { // callback implementation } int main(int argc, const char argv[]) { int mid = 0; set_stream_callback(streamCB, &mid); } And that works fine. However when I try to

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 declared in this scope please help me. Thank You in advance. The issue here is that funcPtr is declared

I want to have a function pointer that can take various types of parameters. How do I do that? The following example (line 1), I want void (*fp)(int) to be able to take void (*fp)(char*) as well. The following code does not properly compile because I'm passing char* where int is expected so compiling the following code will give you warnings (and won't work properly). void callIt(void (*fp)(int)) { (*fp)(5); } void intPrint(int x) { printf("%d\n", x); } void stringPrint(char *s) { printf("%s\n", s); } int main() { void (*fp1)(int) = intPrint; callIt(fp1); void (*fp2)(char*) = stringPrint;

This question already has an answer here: Why do function pointer definitions work with any number of ampersands '&' or asterisks '*'? 2 answers In the book, "Beginning C from Novice to Professional", the author does not use the address of operator when assigning a function to a function pointer. I typed in the code on my compiler both with and without the address of operator and it compiled and performed as expected both times. Why is this and which way would be preferred in an enterprise/business setting? int sum(int, int); int main(void) { ... int (*pfun)(int, int); pfun = ∑ pfun = sum; ...

I'm writing a delegate class but it fails to take const member functions. Here is a test case : class foo { public: void MemberFunction() { printf("non const member function\n"); } void ConstMemberFunction() const { printf("const member function\n"); } }; template <class C, void (C::*Function)()> void Call(C* instance) { (instance->*Function)(); } int main (int argc, char** argv) { foo bar; Call<foo,&foo::MemberFunction>(&bar); Call<foo,&foo::ConstMemberFunction>(&bar); } Now the compiler (visual studio 2010) gives me an error he cannot convert the const member function to a non-const function

I understand how to declare the type of a function: typedef void (typedef_void_f)(); // typedef_void_f is void() using alias_void_f = void(); // alias_void_f is void() And it can be used to declare function pointers: void function() { std::cout << __PRETTY_FUNCTION__ << '\n'; } typedef_void_f *a = function; // pointer to void() alias_void_f *b = function; // pointer to void() For member function pointers the syntax is slightly more complicated: struct S { void function() { std::cout << __PRETTY_FUNCTION__ << '\n'; } }; typedef void (S::*typedef_void_m_f)(); using alias_void_m_f = void (S::*)()