> For the complete documentation index, see [llms.txt](https://docs.arcology.network/arcology-concurrent-programming-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.arcology.network/arcology-concurrent-programming-guide/utility/runtime.md).

# Runtime

The [`Runtime contract`](https://github.com/arcology-network/concurrentlib/blob/main/lib/runtime/Runtime.sol) provides runtime information to developers. It exposes functions to retrieve pseudo-process IDs (PIDs) and pseudo-random UUIDs.

### Random Number Generators

**`pid()`**: Returns the **pseudo-process ID** (PID) of the current execution unit (EU).\
Since all EUs are identical and stateless, `pid()` is useful for generating **deterministic, job-scoped keys or values** within parallel execution.

`uuid()`: Returns a **deterministic, job-scoped pseudo-random UUID**. This value is unique per job and can be used to generate **non-colliding keys or identifiers** within the concurrent execution context.

###

```solidity
```


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