pointers

Cannot Convert from int[][] to int*

I have a 3x3 array that I'm trying to create a pointer to and I keep getting this array, what gives? How do I have to define the pointer? I've tried every combination of [] and *. Is it possible to do this? int tempSec[3][3]; int* pTemp = tempSec; ...

assignment from incompatible pointer type

I have set up the following struct: typedef struct _thread_node_t { pthread_t thread; struct thread_node_t *next; } thread_node_t; ... and then I have defined: // create thread to for incoming connection thread_node_t *thread_node = (thread_node_t*) malloc(sizeof(thread_node_t)); pthread_create(&(thread_node->thread), NULL, c...

How to check if the internal typedef struct of a typedef struct is NULL ?

typedef struct { uint32 item1; uint32 item2; uint32 item3; uint32 item4; <some_other_typedef struct> *table; } Inner_t; typedef struct { Inner_t tableA; Inner_t tableB; } Outer_t; Outer_t outer_instance = { {NULL}, { 0, 1, 2, 3, table_defined_somewhere_else, } }; My question i...

C Pointer Question: &(*struct->struct)

I have a struct defined with the structure as follows (names are different) struct str1 { int field1; struct str2; } And I have a *str1 in a function. I'd like to get a pointer to str2. So I tried &(str1->str2) and was hoping this would return a pointer to str2. Is this incorrect? It doesn't seem to be working. How would I get ...

C++: Vector of objects vs. vector of pointers to new objects?

Hello, I am seeking to improve my C++ skills by writing a sample software renderer. It takes objects consisting of points in a 3d space and maps them to a 2d viewport and draws circles of varying size for each point in view. Which is better: class World{ vector<ObjectBaseClass> object_list; public: void generate(){ objec...

Assign C++ instance method to a global-function-pointer ?

Greetings, My project structure is as follows: \- base (C static library) callbacks.h callbacks.c paint_node.c . . * libBase.a \-app (C++ application) main.cpp In C library 'base' , I have declared global-function-pointer as: in singleheader file callbacks.h #ifndef CALLBACKS_H_ #define CALLBA...

Normal pointer vs Auto pointer (std::auto_ptr)

Code snippet (normal pointer) int *pi = new int; int i = 90; pi = &i; int k = *pi + 10; cout<<k<<endl; delete pi; [Output: 100] Code snippet (auto pointer) Case 1: std::auto_ptr<int> pi(new int); int i = 90; pi = &i; int k = *pi + 10; //Throws unhandled exception error at this point while debugging. cout<<k<<endl; //delete pi; (It...

Remove pointer object whose reference is mantained in three different lists

I am not sure how to approach this problem: 'Player' class mantains a list of Bullet* objects: class Player { protected: std::list< Bullet* > m_pBullet_list; } When the player fires a Bullet, it is added to this list. Also, inside the constructor of bullet, a reference of the same object is updated in CollisionMgr, where Collisio...

Why does perl crash with "*** glibc detected *** perl: munmap_chunk(): invalid pointer"?

#!/usr/bin/env perl use warnings; use strict; use 5.012; use XML::LibXML::Reader; my $reader = XML::LibXML::Reader->new( location => 'http://www.heise.de/' ) or die $!; while ( $reader->read ) { say $reader->name; } At the end of the output from this script I get this error-messages: * glibc detected * perl: munmap_chunk(): ...

How to convert int* to int

Hi guys, Question is how do i convert a pointer to int to an actual int I dont know if this is possible or not, but can someone please advise me Regards Paul ...

Javascript Pointers question with Dates

I noticed this situation in my code (unfortunately), and was able to duplicate it in my own JS file. So I have this code: var date1 = new Date(); // today var date2 = date1; date2 = date2.setDate(date2.getDate() + 1); // what is date1? After this code executes, date1 is today's date + 1! This harkens back to my undergrad days when I...

pointer and reference question (linked lists)

Hi there, I have the following code struct Node { int accnumber; float balance; Node *next; }; Node *A, *B; int main() { A = NULL; B = NULL; AddNode(A, 123, 99.87); AddNode(B, 789, 52.64); etc… } void AddNode(Node * & listpointer, int a, float b) { // add a new node to the FRONT of the list Node *temp; temp = new ...

Returning a struct pointer

Suppose I have the following struct and function returning a pointer: typedef struct { int num; void *nums; int size; } Mystruct; Mystruct *mystruct(int num, int size) { //Is the following correct? Is there a more efficient way? Mystruct mystruct; mystruct.num = num; mystruct.size = size; mystruct.nums = malloc(nu...

Type Declaration - Pointer Asterisk Position

Hello, in C++, the following means "allocate memory for an int pointer": int* number; So, the asterisk is part of the variable type; without it, that would mean something else (that's why I usually don't separate the asterisk from the variable type). Then what is the reason the asterisk is considered something else, instead of being p...

Add 64 bit offset to a pointer

In F#, there's the NativePtr module, but it seems to only support 32 bit offsets for its’ add/get/set functions, just like System.IntPtr does. Is there a way to add a 64 bit offset to a native pointer (nativeptr<'a>) in F#? Of course I could convert all addresses to 64 bit integers, do normal integer operations and then convert the resu...

How to get a char* pointer to a C++ string?

I have a C++ string. I need to pass this string to a function accepting char* parameter, for example - strchr(). a) How do I get that pointer? b) Is there some funtion equivalent to strschr() that works for C++ strings? ...

std::cin >> *aa results in a bus error

I have this a class called PPString: PPString.h #ifndef __CPP_PPString #define __CPP_PPString #include "PPObject.h" class PPString : public PPObject { char *stringValue[]; public: char *pointerToCharString(); void setCharString(char *charString[]); void setCharString(const char charString[]); }; #endif PPString.cpp...

Is there a way to have a bit bucket pointer? (C/C++)

Is there a way to have a bit bucket pointer? A lot of IO (specifically input related) system calls return data to a buffer of a specific size. Is there a trick or way to make a sorta bit bucket pointer, so I can accept any amount of data that will be thrown away. Doing something like "char tmp[INT_MAX]" is crazy. The behavior I am looki...

How can free() immediately followed by assignment of NULL lead to a dangling pointer?

How can the below code result in a dangling pointer. { char *cPointer = malloc ( some constant number ); /* some code */ free ( cPointer ); cPointer = NULL; /* some code */ } ...

C - how to convert a pointer in an array to an index?

In the many search functions of C (bsearch comes to mind) if a result is found, a pointer to the spot in the array is returned. How can I convert this pointer to the index in the array that was searched (using pointer arithmetic, i assume). ...