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# CFBitVectorSetCount(_:_:)

Changes the size of a mutable bit vector.

```
func CFBitVectorSetCount(_ bv: CFMutableBitVector!, _ count: CFIndex)
```

## Parameters

`bv`

The bit vector to modify.

`count`

The new size for `bv`. If `count` is greater than the current size of `bv`, the additional bit values are set to `0`.

## Discussion

If `bv` was created with a fixed capacity, you cannot increase its size beyond that capacity.

## See Also

[`CFBitVectorCreateMutable(_:_:)`](/documentation/CoreFoundation/CFBitVectorCreateMutable(_:_:))

Creates a mutable bit vector.

[`CFBitVectorCreateMutableCopy(_:_:_:)`](/documentation/CoreFoundation/CFBitVectorCreateMutableCopy(_:_:_:))

Creates a new mutable bit vector from a pre-existing bit vector.

[`CFBitVectorGetCount(_:)`](/documentation/CoreFoundation/CFBitVectorGetCount(_:))

Returns the number of bit values in a bit vector.


---

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