function-pointers

I'm a little confused about the correct syntax for assigning a function pointer to a variable. If I have a function foo int foo(); and I am assigning a pointer to foo to variable bar void * bar; it does not seem to matter if I use bar = foo; // or bar = &foo; It seems to me that only one of these should be correct or am I missing something? foo and &foo values are equivalent in C and have same type. The & operator here is correct but redundant. Note that assigning a function pointer to a void * is not valid in C. void *fp1 = foo; // invalid int (*fp2)() = foo; // valid int (*fp3)() = &foo; //

For my Java game server I send the Action ID of the packet which basically tells the server what the packet is for. I want to map each Action ID (an integer) to a function. Is there a way of doing this without using a switch? What about this one? HashMap<Integer, Runnable> map = new HashMap<Integer, Runnable>(); map.put(Register.ID, new Runnable() { public void run() { functionA(); } }); map.put(NotifyMessage.ID, new Runnable() { public void run() { functionB(); } }); // ... map.get(id).run(); (If you need to pass some arguments, define your own interface with a function having a suitable

I only just started learning Python and found out that I can pass a function as the parameter of another function. Now if I call foo(bar()) it will not pass as a function pointer but the return value of the used function. Calling foo(bar) will pass the function, but this way I am not able to pass any additional arguments. What if I want to pass a function pointer that calls bar(42) ? I want the ability to repeat a function regardless of what arguments I have passed to it. def repeat(function, times): for calls in range(times): function() def foo(s): print s repeat(foo("test"), 4) In this case

How can I create a "function pointer" (and (for example) the function has parameters) in C? http://www.newty.de/fpt/index.html typedef int (*MathFunc)(int, int); int Add (int a, int b) { printf ("Add %d %d\n", a, b); return a + b; } int Subtract (int a, int b) { printf ("Subtract %d %d\n", a, b); return a - b; } int Perform (int a, int b, MathFunc f) { return f (a, b); } int main() { printf ("(10 + 2) - 6 = %d\n", Perform (Perform(10, 2, Add), 6, Subtract)); return 0; } typedef int (*funcptr)(int a, float b); funcptr x = some_func; int a = 3; float b = 4.3; x(a, b); I found this site helpful

This question already has an answer here: Complex C declaration 7 answers From Introduction to the C++11 feature: trailing return types The article claims template <class T> class tmp { public: int i; }; auto foo()->auto(*)()->tmp<int>(*)(){ return 0; } is equivalent to template <class T> class tmp{ public: int i; }; tmp<int> (*(*foo())())() { return 0; } I don't understand the complex function in the second code example. Where should I look at in the beginning? I guess is foo . But the stat right next to foo is going to define foo as a pointer... Based on the first code example, I will

I couldn't find an answer to this anywhere. I just read K&R and saw them calling a function pointer like this: (*ptr)(arg1, arg2); I vividly remember, however, to have seen someone using them like this: ptr(arg1, arg2); That might have been in C++, though. How are the rules? Do they differ in C and C++? TL;DR The rules in C and C++ are the same, there's no difference between the two. What does the C++ Standard ( n3797 ) say? 5.2.2p1 Function call [expr.call] A function call is a postfix expression followed by parentheses containing a possible empty, comma-separated list of initializer-clauses

I think they are called functors? (it's been a while) Basically, I want to store a pointer to a function in a variable, so I can specify what function I want to use from the command line. all the functions return and take the same values. unsigned int func_1 (unsigned int var1) unsigned int func_2 (unsigned int var1) function_pointer = either of the above? so then I could call it by going: function_pointer(my_variable)? EDIT: as per @larsmans's suggestion, I've gotten this: Config.h: class Config { public: unsigned static int (*current_hash_function)(unsigned int); }; Config.cpp: #include

In linux kernel source code, added this lines in tasklet_action code: printk("tasklet_action = %p\n" , *tasklet_action); printk("tasklet_action = %p\n" , &tasklet_action); printk("tasklet_action = %p\n" , tasklet_action); In the output I get: tasklet_action = c03441a1 tasklet_action = c03441a1 tasklet_action = c03441a1 But when searching it in the system.map file the tasklet_action address is at c03441a0 so there is an offset of 1 byte. Why do I have this offset? Is it always an one byte offset? My guess is that you are running on ARM in Thumb mode , or on some other architecture that uses the