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Questions tagged [dereference]

Anything related to pointer dereference, i.e. the process of determining the object which the pointer is referring to. Languages having pointer variables usually have a special operator to perform dereferencing of pointers (e.g. in C and C++, if `p` is a valid pointer, `*p` is the object pointed to by `p`).

Anything related to pointer dereference, i.e. the process of determining the object which the pointer is referring to. Languages having pointer variables usually have a special operator to perform dereferencing of pointers (e.g. in C and C++, if p is a valid pointer, *p is the object pointed to by p).

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In this function is defective since dereferencing null is not valid so i want to change code

long cread(long *xp) { return (xp? *xp : 0); } It is invalid since it could attempt to read from a null address So the solution suggested this code long cread_alt(long *xp){ long tem = 0; if(*xp > 0){ tem = *xp; } return tem; But I…
user10430594
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How is this constructor code taking pointers as arguments?

The code below has three arguments of the type double*. The code is part of an Arduino PID library and the user would typically give a reading of an analogue port or some kind of sensor as the argument for the "input" term and some fixed value or…
Ozymandias
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Dereferencing Pointer Array in C

I have a problem in this code segment printf("\nIn Func: %s", (*article[ctr]).artname); I use Code:Blocks and get the error "undefined reference to WinMain@16", article is a pointer array shouldn't I access it just by dereferencing it? I also tried…
Dominik
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Perl reference Dereferencing for @var1 = [($a, $b)]

I have below expression in perl @var1 = [($a, $b)] Can anyone help me to deference the value stored in var1.
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Why does pointer to array (done by &array) equal the array itself?

So I almost went all hurr durr on my classmates when they wrote that &array gives you address of the first element But turns out they are right. This sounds like inconsistency to me. We're talking about array defined like this: int numbers[] =…
Tomáš Zato
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SegFault when dereferencing integer from void ptr

This is my code, Tuple.c, it produces a SegFault at the line with a comment saying so: #include #include #include void dbwait(); typedef struct STuple { int tSize; void** values; } Tuple; Tuple*…
Ashley
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Dereferencing this pointer gives me -46, but I am not sure why

This is a program I ran: #include int main(void) { int y = 1234; char *p = &y; int *j = &y; printf("%d %d\n", *p, *j); } I am slightly confused about the output. What I'm seeing is: -46 1234 I wrote this program as an…
anon
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If a program contains the following code, it may crash. Why?

int *x; { int y; x = &y; } *x = 5; I think the problem is that x = &y should be changed to x = y. However, I still don't know why it would crash?
Leon Ma
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What is the explanation for the output of the following C program?

I came across the following code on geeksquiz.com but could not understand how the expressions involving prefix, postfix and dereference operators are evaluated in C: #include #include int main(void) { int i; int *ptr =…
S K
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C++ Convert number to pointer of type?

I have the following bit of code: int* anInt = new int(5); uintptr_t memAddr = (uintptr_t)&anInt; Log("memAddr is: " + std::to_string(memAddr)); int* anotherInt = (int*)&memAddr; Log("anInt is: " + std::to_string(*anInt)); Log("anotherInt is: " +…
ManIkWeet
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C++ dereferencing an instance

I'm new to C++ and I'm trying to dry up my code, for example: void gethit () { Gert.hitbox(AA.x, AA.damage); Gert.hitbox(AB.x, AB.damage); Gert.hitbox(AC.x, AC.damage); Gert.hitbox(AD.x, AD.damage); Gert.hitbox(Terbil.x,…
Garrett Hale
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Segmentation fault in C when trying to reference first element in char *

I have written a C function which the goal in mind to see if the chars 'b' is in the char array 'a'. I am new to pointers and learning. void contains (char const *a, char const *b) { } and am calling it as: contains("abc", "b"); From my…
asdf
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Int cannot be deferenced error

I am trying to take the user input from one method and use it in another. I am confused about the error because they are both of type int. public static void move() { System.out.println("What do you want to do?"); Scanner scan = new…
user2181402
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Perl get value of a hash in a hash

I have a Perl hash and I dont know what its content looks like. When I print out its keys and values (check attached hash loop picture) I get for values what looks like a string that contains another hash for each value (check output of hash loop…
VBAidontgetitDUDE
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Assignment doesn't work but address of with the dereference operator does?

I've been playing around with C++ (just starting out), and I'm trying to make a program that needs a function to count the lines in C++. However, I've encountered weird behavior where normal assignment doesn't work, but assignment through address…
nshoo
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