In order to obtain the address of the account contract (or any other contract, in the case that the function was invoked by a contract) that invoked our function, we can use the get_caller_address() library function:

from starkware.starknet.common.syscalls import get_caller_address

// ...

let (caller_address) = get_caller_address();
get_caller_address() returns the address of the source contract that called this contract. It can be the address of the account contract or the address of another contract (if the function was invoked by another contract). When the contract is called directly (rather than through a contract), the function returns 0.

Note that if you use get_caller_address() in a function foo() that was called by another function bar() within your contract, it will still return the address of the contract that invoked bar() (or 0 if it was invoked directly).



Hello! I was wondering whether it was possible to check if a certain address has code in Cairo.
In Solidity, we do something like:

```
assembly {
  codeSize := extcodesize(contractAddress)
}
or just:
uint256 codeSize = contractAddress.code;
```
I was wondering if there was a way to check something like this in cairo? I checked the syscalls file but didn't find anything promising there.

Thank you in advance!

How to check if a contract has been deployed at a certain address in cairo?

does anyone know of newsletters that focus on StarkNet or the zk ecosystem in general?

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Does anyone know of newsletters that focus on StarkNet or the zk ecosystem in general?

How to use Access Control in Cairo securely? What library can I use for implementing it?

How to use Access Control in Cairo language securely?

Hello, anyone able to advise what the etherscan equivalent for starknet is ?

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

What the etherscan equivalent for starknet is ?

Is there a way/a tool that can automatically generate events for Cairo functions, since pretty much all of my events follow the same format


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/221)_

Cairo Automatic Events

Hello! This is day 12 of the 17 days of the Cairo Challenge. And I have no idea how to solve the [playground](https://www.cairo-lang.org/playground/) exercise “Structs.  Perhaps you can help me?

```
// In this challenge you're going to implement a stack using a linked list.
//
// Add the missing code so that main() runs successfully.

from starkware.cairo.common.registers import get_fp_and_pc

struct Node {
    // A pointer to the next node in the stack.
    next: Node*,

    // The value of the node.
    value: felt,

    // The number of elements in the stack.
    size: felt,
}

// Returns an empty stack.
func empty_stack() -> (stack: Node*) {
    alloc_locals;
    local new_node: Node;
    assert new_node.next = cast(0, Node*);
    assert new_node.value = 0;
    assert new_node.size = 0;

    // The usage of get_fp_and_pc() here is necessary in order
    // to access the address of a local variable (&new_node).
    // You can read more about get_fp_and_pc() [here](https://cairo-lang.org/docs/how_cairo_works/functions.html#retrieving-registers).
    let (local __fp__, _) = get_fp_and_pc();
    return (stack=&new_node);
}

// Adds a node to the top of the stack.
// Returns the updated stack (since Cairo is immutable, you can still use the
// old copy of the stack).
func push(stack: Node*, value: felt) -> (stack: Node*) {
    alloc_locals;
    local new_node: Node;
    // Fix and uncomment below.
    // assert new_node.next = ...
    // assert new_node.value = ...
    // assert new_node.size = ...

    let (__fp__, _) = get_fp_and_pc();
    return (stack=&new_node);
}

// Removes the top element of the stack.
// Returns the updated stack and the element that was removed.
func pop(stack: Node*) -> (stack: Node*, value: felt) {
    return (stack=stack.next, value=stack.value);
}

// Returns the value of the n-th element from the top of the stack.
func stack_at(stack: Node*, n: felt) -> (value: felt) {
    if (n == 0) {
        // Add your code here.
    }

    // Add your code here.
}

func main() -> () {
    alloc_locals;
    // Start with an empty stack.
    let (stack) = empty_stack();
    // Push 1, 10, 100.
    let (stack) = push(stack, 1);
    let (stack) = push(stack, 10);
    let (local stack) = push(stack, 100);

    // Check the size of the stack.
    assert stack.size = 3;

    // Query the stack at indices 0, 1 and 2.
    let (value) = stack_at(stack, 0);
    assert value = 100;
    let (value) = stack_at(stack, 1);
    assert value = 10;
    let (value) = stack_at(stack, 2);
    assert value = 1;

    // Pop the top 2 values (100 and 10) and push 1000.
    let (stack, value) = pop(stack);
    assert value = 100;
    let (stack, value) = pop(stack);
    assert value = 10;
    let (local stack) = push(stack, 1000);

    // Query the stack at indices 0 and 1.
    let (value) = stack_at(stack, 0);
    assert value = 1000;
    let (value) = stack_at(stack, 1);
    assert value = 1;

    return ();
}
```

---

> Answers to this question are a part of the ✨ 17 days of Cairo Lang with Playground & Newton. ✨
> 

*Vote for your favorite answer - the best answer will win a $10 award. A new day – a new reward! During the next 17 days, our goal is to attract more developers to the Cairo language and to systematize the knowledge of Cairo lang. [Read rules](https://www.notion.so/17-days-of-Cairo-Lang-with-Newton-550dfcda6a2d449ca468be293c776578)*

How to create Structs in Cairo Lang for StarkNet?

Is there an equivalent of return (true) in cairo on Starknet?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/686)_

Cairo: How to return true from a function?

following this page from the docs https://starknet.io/docs/hello_starknet/intro.html
I copied the code, compiled it using starknet compile, and when I go to declare it using starknet declare Im getting 
Status code: 500; text: {"code": "StarknetErrorCode.ENTRY_POINT_NOT_FOUND_IN_CONTRACT", "message": "Entry point <address>caed693fa4008dcdb4963b3 not found in contract with class hash <address>975148f6af3e9abddfdc701."}
Any help would be appreciated.

_This question was originally posted on [StarkNet Discord](https://www.newton.so/view?tags=discord)_

Popular tags

How to check if a contract has been deployed at a certain address in cairo?

1 answers

Your answer

Related

You may find useful