---
title: "BNNSRandomGeneratorGetState(_:_:_:)"
framework: accelerate
role: symbol
role_heading: Function
path: "accelerate/bnnsrandomgeneratorgetstate(_:_:_:)"
---

# BNNSRandomGeneratorGetState(_:_:_:)

Returns the state of a random number generator.

## Declaration

```swift
func BNNSRandomGeneratorGetState(_ generator: BNNSRandomGenerator?, _ state_size: Int, _ state: UnsafeMutableRawPointer) -> Int32
```

## Parameters

- `generator`: The random number generator.
- `state_size`: The size of the state buffer, in bytes.
- `state`: A pointer to the state.

## Discussion

Discussion Use the BNNSRandomGeneratorGetState(_:_:_:) and BNNSRandomGeneratorSetState(_:_:_:) functions to capture and restore a random number generator’s state. The following code creates a random number generator and captures its initial state. The code calls BNNSRandomFillUniformInt(_:_:_:_:) twice and copies the random values into the arrays a and b. The BNNSRandomGeneratorSetState(_:_:_:) function restores the generator to its initial state, and the final call to BNNSRandomFillUniformInt(_:_:_:_:) populates the descriptor so that the values in arrays a and c are equal. let data = UnsafeMutableBufferPointer<Int16>.allocate(capacity: 8) var descriptor = BNNSNDArrayDescriptor(flags: BNNSNDArrayFlags(0),                                        layout: BNNSDataLayoutVector,                                        size: (10, 0, 0, 0, 0, 0, 0, 0),                                        stride: (0, 0, 0, 0, 0, 0, 0, 0),                                        data: data.baseAddress!,                                        data_type: BNNSDataType.int16,                                        table_data: nil,                                        table_data_type: BNNSDataType.int16,                                        data_scale: 1, data_bias: 0)

guard let randomNumberGenerator = BNNSCreateRandomGenerator(BNNSRandomGeneratorMethodAES_CTR,                                                             nil) else {     return }

// Allocate memory to store state. let stateSize = BNNSRandomGeneratorStateSize(randomNumberGenerator) let state = UnsafeMutableRawPointer.allocate(byteCount: stateSize,                                              alignment: 0)

// Store the random number generator's state. BNNSRandomGeneratorGetState(randomNumberGenerator,                             stateSize,                             state)

BNNSRandomFillUniformInt(randomNumberGenerator,                          &descriptor,                          -10,                          10)

let a = Array(data)

BNNSRandomFillUniformInt(randomNumberGenerator,                          &descriptor,                          -10,                          10)

let b = Array(data)

// Set the random number generator's state to its initial state. BNNSRandomGeneratorSetState(randomNumberGenerator,                             stateSize,                             state)

BNNSRandomFillUniformInt(randomNumberGenerator,                          &descriptor,                          -10,                          10)

let c = Array(data)

print(a.elementsEqual(c)) // prints "true"

data.deallocate() state.deallocate() BNNSDestroyRandomGenerator(randomNumberGenerator)

## See Also

### Random number generation

- [BNNS.RandomGenerator](accelerate/bnns/randomgenerator.md)
- [BNNSCreateRandomGenerator(_:_:)](accelerate/bnnscreaterandomgenerator(_:_:).md)
- [BNNSCreateRandomGeneratorWithSeed(_:_:_:)](accelerate/bnnscreaterandomgeneratorwithseed(_:_:_:).md)
- [BNNSRandomGeneratorMethod](accelerate/bnnsrandomgeneratormethod.md)
- [BNNSRandomGenerator](accelerate/bnnsrandomgenerator.md)
- [BNNSRandomFillUniformInt(_:_:_:_:)](accelerate/bnnsrandomfilluniformint(_:_:_:_:).md)
- [BNNSRandomFillUniformFloat(_:_:_:_:)](accelerate/bnnsrandomfilluniformfloat(_:_:_:_:).md)
- [BNNSRandomFillNormalFloat(_:_:_:_:)](accelerate/bnnsrandomfillnormalfloat(_:_:_:_:).md)
- [BNNSRandomFillCategoricalFloat(_:_:_:_:)](accelerate/bnnsrandomfillcategoricalfloat(_:_:_:_:).md)
- [BNNSRandomGeneratorStateSize(_:)](accelerate/bnnsrandomgeneratorstatesize(_:).md)
- [BNNSRandomGeneratorSetState(_:_:_:)](accelerate/bnnsrandomgeneratorsetstate(_:_:_:).md)
- [BNNSDestroyRandomGenerator(_:)](accelerate/bnnsdestroyrandomgenerator(_:).md)