> For the complete documentation index, see [llms.txt](https://quantumwing.gitbook.io/quantumwing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://quantumwing.gitbook.io/quantumwing/smart-contract-library/overview.md).

# Overview

Reference contracts shipped in contracts/

QuantumWing ships eleven reference contracts under [`contracts/`](https://github.com/quantumwing/protocol/tree/master/contracts). Each contract is a `no_std` Rust crate that compiles to WASM and runs on the QWVM.

The contracts double as:

* **Reference implementations** for token / DEX / governance / oracle developers
* **Foundation primitives** that downstream contracts can build on (a stablecoin needs an oracle; a DEX needs a token; a DAO needs a governance vote)
* **Audit surface** for the external security audit (Tier A-5 in [Pre-Launch Status](/quantumwing/roadmap/pre-launch-status.md))

## Token standards

| Page                                                     | Folder                   | Size   | Purpose                             |
| -------------------------------------------------------- | ------------------------ | ------ | ----------------------------------- |
| [QRC-20](/quantumwing/smart-contract-library/qrc20.md)   | `contracts/qrc20-rust/`  | 6.4 KB | Fungible tokens (ERC-20-equivalent) |
| [QRC-721](/quantumwing/smart-contract-library/qrc721.md) | `contracts/qrc721-rust/` | 8 KB   | NFTs (ERC-721-equivalent)           |
| [WQGEN](/quantumwing/smart-contract-library/wqgen.md)    | `contracts/wqgen-rust/`  | 9 KB   | Wrapped native QWING                |

## Account abstraction

| Page                                                       | Folder                                                                          | Size     | Purpose                                        |
| ---------------------------------------------------------- | ------------------------------------------------------------------------------- | -------- | ---------------------------------------------- |
| [ERC-4337](/quantumwing/smart-contract-library/erc4337.md) | `contracts/aa-entrypoint-rust/` (10 KB) + `contracts/aa-account-rust/` (5.1 KB) | combined | Singleton EntryPoint + reference smart account |

## DeFi primitives

The DeFi-flavored contracts (oracle, DEX, stablecoin, governance) live under [DeFi Primitives](/quantumwing/defi-primitives/overview.md). They share the same Rust/WASM ABI conventions — see below.

## Wallet contracts

| Page                                                             | Folder                   | Size    | Purpose                       |
| ---------------------------------------------------------------- | ------------------------ | ------- | ----------------------------- |
| [QWSafe Multi-sig](/quantumwing/wallets-and-clients/multisig.md) | `contracts/qwsafe-rust/` | 15.5 KB | M-of-N owner threshold wallet |

## Common ABI conventions

All reference contracts share these conventions:

* Exported functions are `extern "C" fn name() -> u32` returning a status code.
* Arguments are written by the host into a fixed-size `ARG_BUFFER` static (256 bytes by default). The contract exports `get_arg_buffer_ptr()` so the host can locate it.
* Return values are written into a fixed-size `RET_BUFFER` static and the host reads them back via `get_ret_buffer_ptr()` + `get_ret_len()`.
* Storage keys are ASCII strings of the form `prefix:field` or `prefix:{address}` (32 hex chars). 32 bytes is the maximum key length; longer keys are hashed into a 32-byte slot.
* Storage values are raw bytes (not RLP, not JSON) — encoding is the contract's responsibility.
* Events are EVM-shaped: `topics[0] = keccak256("EventName(arg0,arg1,...)")`, `topics[1..]` are 32-byte indexed parameters, `data` is ABI-encoded non-indexed parameters.

## Build all contracts

```bash
cd contracts
for d in */; do
  cd "$d"
  if [ -f "Cargo.toml" ]; then
    cargo build --release --target wasm32-unknown-unknown
  fi
  cd ..
done
```

Output WASM at:

```
contracts/<name>-rust/target/wasm32-unknown-unknown/release/<name>.wasm
```

## Status codes

```
0   OK
1   NotInitialized
2   AlreadyInitialized
3   Unauthorized
4   InvalidArgument
5   InsufficientBalance
6   InsufficientAllowance
7   StorageMissing
8   ReentrancyDetected
9   ArithmeticOverflow
10  ZeroAddress
11+ contract-specific
```

## Related

* [QWVM Overview](/quantumwing/smart-contracts/qwvm.md) — host functions and execution model
* [WASM Gas Metering](/quantumwing/smart-contracts/wasm-gas-metering.md) — gas costs at the bytecode level


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