# extractCSharpControlFlow

**Kind:** Function

**Source:** [`atloria-monorepo/libs/parser-core/src/parsers/backend/csharp-control-flow.ts`](https://github.com/sherkety/atloria/blob/main/atloria-monorepo/libs/parser-core/src/parsers/backend/csharp-control-flow.ts#L361)

Read the guards and catches out of a span of C# source.

`startLine`/`endLine` bound the scan to one class without changing the coordinate space: the
line numbers reported are always the file's own, so an entity spanning lines 40–300 reports a
guard at line 57 and not at line 17.

Only an `if` whose branch is a single `throw` or `return` counts as a guard. A condition
wrapping a block of real work is control flow but not a refusal, and calling it one would put a
sentence on the page that misdescribes the code — PAMS has
`if (typeId <= 0) { await logic.LogException(…); return BadRequest(); }`, which logs before it
refuses and so is deliberately not reported as a bare refusal.

## Signature

```ts
function extractCSharpControlFlow(source: string, startLine: number, endLine: number): ControlFlow
```

## Parameters

| Name | Type |
|---|---|
| `source` | `string` |
| `startLine` | `number` |
| `endLine` | `number` |

**Returns:** `ControlFlow`