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Apr 24, 2025
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Update task-expressions.md #45850

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Update task-expressions.md
Lanayx Apr 17, 2025
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Update docs/fsharp/language-reference/task-expressions.md
BillWagner Apr 24, 2025
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22 changes: 22 additions & 0 deletions docs/fsharp/language-reference/task-expressions.md
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Expand Up @@ -68,6 +68,28 @@ let makeTask() =
makeTask() |> ValueTask<int>
```

## `and!` bindings (starting from F# 10)

Within task expressions, it is possible to concurrently await for multiple asynchronous operations (`Task<'T>`, `ValueTask<'T>`, `Async<'T>` etc). Compare:

```fsharp
// We'll wait for x to resolve and then for y to resolve. Overall execution time is sum of two execution times.
let getResultsSequentially() =
task {
let! x = getX()
let! y = getY()
return x, y
}

// x and y will be awaited concurrently. Overall execution time is the time of the slowest operation.
let getResultsConcurrently() =
task {
let! x = getX()
and! y = getY()
return x, y
}
```

## Adding cancellation tokens and cancellation checks

Unlike F# async expressions, task expressions do not implicitly pass a cancellation token and don't implicitly perform cancellation checks. If your code requires a cancellation token, you should specify the cancellation token as a parameter. For example:
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