Basic
- What's New in Vyper 0.4
- Hello World
- Data Types - Values
- Data Types - References
- Dynamic Arrays
- Constructor
- Private and Public State Variables
- Constants
- Immutable
- Function
- Internal and External Functions
- View and Pure Functions
- If Else
- For Loop
- Error
- Event
- Payable
- Default Function
- Send Ether
- Interface
- Raw Call
- Delegate Call
- Hash Function
- Verify Signature
- Re-entrancy Lock
- Create New Contract
- Self Destruct
- Imports
- Modules
- Unsafe Math
- Debug with Print
Re-Entrancy Lock
For the most up to date version of this content, please see Re-Entrancy Lock (Code Example) on Cyfrin.io
Vyper has a handy way to secure your contract from re-entrancy.
A re-entrancy lock can be created on a function with @nonreentrant.
Contract with re-entrancy lock
# pragma version ^0.4.0
@external
@nonreentrant
def func():
raw_call(msg.sender, b"", value=0)
Contract without re-entrancy lock
# pragma version ^0.4.0
@external
def func():
raw_call(msg.sender, b"", value=0)
Contract to test re-entrancy
# pragma version ^0.4.0
interface ILock:
def func(): nonpayable
count: public(uint256)
@external
@payable
def __default__():
if self.count < 2:
self.count += 1
extcall ILock(msg.sender).func()
@external
def reset():
self.count = 0
@external
def test_lock(to: address):
extcall ILock(to).func()
Try on Smart Contract Engineer
