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# CFBitVectorSetBitAtIndex(_:_:_:)

Sets the value of a particular bit in a bit vector.

```
func CFBitVectorSetBitAtIndex(_ bv: CFMutableBitVector!, _ idx: CFIndex, _ value: CFBit)
```

## Parameters

`bv`

The bit vector to modify.

`idx`

The index of the bit value to set. The index must be in the range `0…N-1`, where `N` is the count of the vector.

`value`

The bit value to which to set the bit at index `idx`.

## See Also

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

Returns the number of bit values in a bit vector.


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