# withUnsafeBufferPointer(_:) Calls the given closure with a pointer to the buffer’s contiguous storage. ``` func withUnsafeBufferPointer(_ body: (UnsafeBufferPointer) throws -> R) rethrows -> R ``` ## Parameters `body` A closure with an parameter that points to the contiguous storage for the pixel buffer. ## Return Value The return value, if any, of the body closure parameter. ## Discussion You can use this function to simplify interoperation with other libraries and frameworks. For example, the following code uses Accelerate’s library to raise each pixel value to the power of `1 / 2.2`: ```swift let srcBuffer = vImage.PixelBuffer(pixelValues: [0.1, 0.2, 0.3, 0.4], size: vImage.Size(width: 4, height: 1), pixelFormat: vImage.PlanarF.self) let destBuffer = vImage.PixelBuffer(size: srcBuffer.size, pixelFormat: vImage.PlanarF.self) var exponent = Float(1 / 2.2) var count = Int32(4) srcBuffer.withUnsafeBufferPointer { src in destBuffer.withUnsafeMutableBufferPointer { dest in vvpowsf(dest.baseAddress!, &exponent, src.baseAddress!, &count) } } ``` > Note: > The contiguous storage may include space outside of the buffer’s width that doesn’t contain image information. The storage contains `rowStride * channelCount * height` elements. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)