pointers Questions
2
Solved
I have a pointer to an array element which is used as an argument in a function and is moved along the array inside said function via the "++" operation. I would like the updated position...
3
I have a type:
struct Foo {
memberA: Bar,
memberB: Baz,
}
and a pointer which I know is a pointer to memberB in Foo:
p: *const Baz
What is the correct way to get a new pointer p: *const Foo...
8
Solved
I get this message when compiling C++ on gcc 4.3
error: ‘NULL’ was not declared in this scope
It appears and disappears and I don't know why. Why?
Thanks.
7
Solved
In a system where registered objects must have unique names, I want to use/include the object's this pointer in the name. I want the simplest way to create ??? where:
std::string name = ???(this);...
13
Solved
How do I understand following complicated declarations?
char (*(*f())[])();
char (*(*X[3])())[5];
void (*f)(int,void (*)());
char far *far *ptr;
typedef void (*pfun)(int,float);
int **(*f)(i...
Olshausen asked 19/9, 2009 at 16:8
3
Solved
How do I declare a pointer to a character array in C?
7
Solved
The following line (pure c) compiles cleanly on windows (win7 64 bits + codeblocks 13 + mingw32) and debian (wheezy 32 bits + codeblocks 10 + gcc) but raises warning on kali (64 bits + codeblocks +...
6
Solved
I defined a linked list in C++. I am trying to set a NULL value to the variable head (in the constructor of Movie_LinkedList), but I got:
movie.h(40): error C2065: 'NULL' : undeclared identifier
pl...
3
Solved
#include <iostream>
#include <memory> // unique_ptr
using namespace std;
int main()
{
std::unique_ptr<char*> char_ptr;
char_ptr = (char*)"anisha";
return 0;
}
I want to as...
Decamp asked 27/11, 2018 at 6:44
6
Is there a way to "convert" a reference to pointer in c++? In example below, func2 has already defined prototype and I can't change it, but func is my API, and I'd like to either pass both paramete...
4
Solved
It is very unclear for me in which case I would want to use a value receiver instead of always using a pointer receiver.
To recap from the docs:
type T struct {
a int
}
func (tv T) Mv(a int) int {...
6
Solved
What is uintptr_t and what can it be used for?
12
Solved
Recently I have come across this problem which I am unable to understand by myself.
What do these three Expressions REALLY mean?
*ptr++
*++ptr
++*ptr
I have tried Ritchie. But unfortunately was un...
4
Solved
I'm using a vector of pointers to objects. These objects are derived from a base class, and are being dynamically allocated and stored.
For example, I have something like:
vector<Enemy*> En...
2
I have the issue that I cannot properly close mmap-s in Python after I created a pointer to them. My use case is that I open files (usually that is UIO-devices to work with hardware, but the issue ...
Teague asked 16/11, 2018 at 14:38
3
Solved
I have a singly-linked-list, L, and create a pointer to this list P. It seems like sometimes modifying P changes the actual list, while other times modifying P does nothing to the actual list L and...
Furfur asked 8/11, 2019 at 1:53
5
Solved
As shown below, I want to pass a variable defined by char **x to a function as read only.
A reference book shows linear search source code that executes linear search to a variable defined by int *...
0
I am writing a C++ tagged pointer. I have a question about whether the operations I use to implement its basic functionality cause undefined behavior:
When constructing a tagged pointer given a po...
Poeticize asked 23/1 at 3:16
2
Solved
I am trying to wrap my mind around pointers in Assembly.
What exactly is the difference between:
mov eax, ebx
and
mov [eax], ebx
and when should dword ptr [eax] should be used?
Also when I try to...
6
Solved
I am learning C and am having trouble passing the pointer of a 2D array to another function that then prints the 2D array. Any help would be appreciated.
int main( void ){
char array[50][50];
i...
2
Solved
I am learning about constexpr variables using the books listed here. In particular I read in C++ Primer that:
Variables declared constexpr are implicitly const and must be initialized with constan...
Whitherward asked 15/10, 2022 at 15:12
15
How many pointers (*) are allowed in a single variable?
Let's consider the following example.
int a = 10;
int *p = &a;
Similarly we can have
int **q = &p;
int ***r = &q;
and so o...
Carbonate asked 10/4, 2012 at 10:34
4
How can you interpret the following line of code?
int (*arrayABC)[10];
In my textbook, it says that we have a pointer to a pointer to the 0th element of an integer array.
However, I don't quite...
5
Solved
I have a struct type with a *int64 field.
type SomeType struct {
SomeField *int64
}
At some point in my code, I want to declare a literal of this (say, when I know said value should be 0, or po...
30
Solved
Is there any way to determine (programatically, of course) if a given pointer is "valid"? Checking for NULL is easy, but what about things like 0x00001234? When trying to dereference this kind of p...
Tartuffery asked 15/2, 2009 at 15:45
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