I am trying to use Python's ctypes library to access some methods in the scanning library SANE. This is my first experience with ctypes and the first time I have had to deal with C datatypes in over a year so there is a fair learning curve here, but I think even without that this particular declaration would be troublesome: extern SANE...
Hi, Somewhat unclear to me are references (pointers?) to classes in Visual Basic .Net. The question I am about to ask can be answered by a little bit of testing, but I was wondering if anybody could post a decent explanation (or links, too). If you create a class: Public Class ReferenceClass private myBooleanValue as Boolean = F...
I'm a beginner programmer and I'm learning my first language, C. I'm learning mostly from Deitel and Deitel's C How to Program book, but also using example tasks and things from the university, however I am stuck on one. I have a very very basic understanding of pointers - adding & in front of a variable makes it print an address and ...
Does anyone have any good articles or explanations (blogs, examples) for pointer arithmetic? Figure the audience is a bunch of Java programmers learning C and C++. ...
This problem is from a solved problem in my old question, which is from: http://stackoverflow.com/questions/394763/c-inserting-2d-array-object-into-another-2d-array-object But also created a new problem for me. Please read the question and the solution in the link to understand my problem. The solution in the previous question was to ma...
Imagine I am doing something like this: void *p = malloc (1000); *((char*)p) = some_opcode; *((char*)p+1) = another_opcode; // for the sake of the example: the opcodes are ok .... etc... How can I define a function pointer to call p as if it was a function? (i'm using VC++ 2008 express). Thanks ...
I'm used to doing Java programming, where you never really have to think about pointers when programming. However, at the moment I'm writing a program in C++. When making classes that have members of other classes, when should I use pointers and when should I not? For example, when would I want to do this: class Foo { Bar b; } As ...
In my experience, everyone names variables like this: int *myVariable; Rather than like this: int* myVariable; Both are valid. It seems to me that the asterisk is a part of the type, not a part of the variable name. Can anyone explain this logic? ...
Hi, I have a structure typedef struct my_s { int x; ... } my_T; my_t * p_my_t; I want to set the address of p_my_t to NULL, tried: memset (&p_my_t, 0, sizeof(my_t*)) This does not look right, what is the correct way of doing this? appreciate it... Amendment to question - asking a radically more complex question: Thank...
I'm writing a sparse matrix class in C++ in which every row and column are arrays of linked lists from a class I created (aptly named: LinkedList). I want to write a class that is a "smart" pointer to one cell in this matrix. In that class, let say LIPointer, I will implement a ++ operator function for moving in the linked lists of the...
My idea of program: I have a dictionary: options = { 'string' : select_fun(function pointer), 'float' : select_fun(function pointer), 'double' : select_fun(function pointer) } whatever type comes single function select_fun(function pointer) gets called. Inside select_fun(function pointer),I will have diff functions for float, double ...
i want to do this simple piece of code work. #include <iostream> #include <windows.h> void printSome (int i) { std::cout << i << std::endl; } void spawnThread (void (*threadName)(int i)) { CreateThread ( 0, // default security attributes 0, // use default stack s...
Hi There is a pointer-to-an-Array of Arrays i.e. NameList in the code. I want the contents of each of the Arrays in the Pointer(NameList) to get printed one by one. The below code is not able do the task. Pls. help. int Data1[] = {10,10}; int Data2[] = {20,20}; int Data3[] = {30,30}; int *NameList[] = {Data1, Data2, Data3}; main()...
Hello, I'm reading some code in the Ogre3D implementation, and I can't understand what does a void*-typed variable could mean. What does a pointer to void means in C++? ...
I want to convert function object to function. I wrote this code, but it doesn't work. #include <iostream> typedef int (*int_to_int)(int); struct adder { int n_; adder (int n) : n_(n) {} int operator() (int x) { return x + n_; } operator int_to_int () { return this->*&adder::operator(); } }; int main(void...
I'm programming C++ with normal pointers, but I have heard about libraries like Boost that implement smart pointers and I have seen that in Ogre3D rendering engine there is a deep use of shared pointers. What's exactly the difference between the three, and should I stick on using just a type of them? Thanks. ...
I have a pointer to pointer array. I am assigning each row in the while loop below and the printf inside the while loop shows each is assigned my id number 1-20. After, out side of the while loop I iterate through the array and every element is written with id 20? Any help is greatly appreciated. (FYI- I am using the Template2doc library...
#include<iostream> class name { public: int a; name():a(0){}; }; void add(name * pname) { pname = NULL; } int main() { name varName(); name * pName = new name(); add(pName); add(&varName);//error C2664: 'add' : cannot convert parameter 1 from 'name __cdecl *)(void)' to 'name *' } ...
I have code similar to this in my application: class A { public: int b; } class C { public: int d; } void DoThings (void *arg1, MYSTERYTYPE arg2); A obj_a; C obj_c; DoThings(&obj_a, &A::b); DoThings(&obj_c, &C::d); The question is - What should MYSTERYTYPE be? neither void* nor int work, despite the value &A::b being printed j...
Consider: class C { private: class T {int a, b;}; }; C::T *p; As expected, this produces a compilation error saying that C::T is private in the context of Line 6. Now change this to pointer-to-member: class C { private: class T {int a, b;}; }; int C::T::*p; This time around, gcc version 3.2.3 still makes the same complaint...