Hey, you can try to fix it: `let (local bud_ptr) = alloc()`

### How to fix this?

```python
./main.cairo:23:13: While expanding the reference 'bud_ptr' in:
    bud=bud,
            ^*****^
./main:20:9: Error at pc=0:2482:
Unknown value for memory cell at address 1:8.
```

Newton

How to fix `bud_ptr`

I am currently running this code

```
func main() {

    let x = [ap];
    [ap] = 1, ap++;

    [ap] = 2, ap++;

    [ap] = x, ap++;
    jmp rel -1;  // Jump to the previous instruction.
}

And what is happening is that "x" is alternating between 1 and 2 and I couldn't figure out why.

Also, it wasn't very clear to me what a "Revoked Reference" means. Is it when you cannot access a certain [ap] when running a specific function?

This is the link to the exercise:
https://www.cairo-lang.org/docs/how_cairo_works/consts.html#revoked-references

Revoked References exercise from Cairo-lang

Everyone knows that secure code is essential. Can someone explain what is reentrancy?
I am curious about the reentrancy attack in StarkNet – is it a problem in Cairo Language and how to protect my smart contract from this attack?

How to protect my contract from reentrancy in Cairo Language / StarkNet?

Guys, what`s ArgentX?

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

What is ArgentX?

How do I put funds into my newly created account from the ape console?


ApeWorX: How do I fund newly created accounts from the ape console?

When deploying contract2 from contract1 in Cairo, I need to get the CLASS_HASH. How do I achieve this?


ㅤ
_This question was originally posted on [Triality](https://triality.org/question/554)_

Getting the CLASS_HASH of a contract in Cairo

Hi, 
Would anyone have a link or know how fast blocks would be generated on StarkNet after Regenesis ?
I am working on a project where I mint an NFT which can be burnt to mint other NFTs. Hence, I'd like to know how much minimum time there will be between these two mints transactions.

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

Would anyone have a link or know how fast blocks would be generated on StarkNet after Regenesis ?



I've written a couple contracts for L1 (Ethereum) and L2 (Starknet) and have them communicate [here](https://www.cairo-lang.org/docs/hello_starknet/l1l2.html).


I can see that L1 sent the message I'm expecting, see [this TX on etherscan](https://goerli.etherscan.io/tx/0x28f3c1021672431d81b34cc141b49a927ae9c989b1521f12b971c45e9717b1f6). The last message in there however never executed on my L2 contract. I'm trying to figure out whether the L2 Sequencer has invoked the handler function of my contract and if so, whether/how it failed.


Does anyone here know how to find the TX that handles the invoke on L2? Or any other ideas/tools that would help figuring out why the l1\_handler never executed/failed?



ㅤ
_This question was originally posted on [Stack Overflow](https://stackoverflow.com/questions/72239816/checking-result-of-an-l1-l2-message-invoke-in-starknet)_

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