# RawSpan `RawSpan` represents a contiguous region of memory which contains initialized bytes. ``` @frozen struct RawSpan ``` ## Overview A `RawSpan` instance is a non-owning, non-escaping view into memory. When a `RawSpan` is created, it inherits the lifetime of the container owning the contiguous memory, ensuring temporal safety and avoiding use-after-free errors. Operations on `RawSpan` are bounds-checked, ensuring spatial safety and avoiding buffer overflow errors. ## Topics ### Initializers [`init()`](/documentation/Swift/RawSpan/init()) Create an empty span. [`init(elements: Span)`](/documentation/Swift/RawSpan/init(elements:)) View a typed span as a raw span. [`init(unsafeElements: Span)`](/documentation/Swift/RawSpan/init(unsafeElements:)) Unsafely view a typed span as a raw span. ### Instance Properties [`var byteCount: Int`](/documentation/Swift/RawSpan/byteCount) The number of bytes in the span. [`var byteOffsets: Range`](/documentation/Swift/RawSpan/byteOffsets) The indices that are valid for subscripting the span, in ascending order. [`var isEmpty: Bool`](/documentation/Swift/RawSpan/isEmpty) A Boolean value indicating whether the span is empty. ### Instance Methods [`func byteOffsets(of: borrowing RawSpan) -> Range?`](/documentation/Swift/RawSpan/byteOffsets(of:)) Returns the byte offsets within this span where the memory represented by other is located, or nil if other is not located within this span. [`func extracting(Range) -> RawSpan`](/documentation/Swift/RawSpan/extracting(_:)-2imhy) Constructs a new span over the bytes within the supplied range of positions within this span. [`func extracting(UnboundedRange) -> RawSpan`](/documentation/Swift/RawSpan/extracting(_:)-3elv4) Constructs a new span over all the bytes of this span. [`func extracting(some RangeExpression) -> RawSpan`](/documentation/Swift/RawSpan/extracting(_:)-8oy0e) Constructs a new span over the bytes within the supplied range of positions within this span. [`func extracting(droppingFirst: Int) -> RawSpan`](/documentation/Swift/RawSpan/extracting(droppingFirst:)) Returns a span over all but the given number of initial bytes. [`func extracting(droppingLast: Int) -> RawSpan`](/documentation/Swift/RawSpan/extracting(droppingLast:)) Returns a span over all but the given number of trailing bytes. [`func extracting(first: Int) -> RawSpan`](/documentation/Swift/RawSpan/extracting(first:)) Returns a span containing the initial bytes of this span, up to the specified maximum length. [`func extracting(last: Int) -> RawSpan`](/documentation/Swift/RawSpan/extracting(last:)) Returns a span containing the trailing bytes of the span, up to the given maximum length. [`func extracting(unchecked: ClosedRange) -> RawSpan`](/documentation/Swift/RawSpan/extracting(unchecked:)-2hjqs) Constructs a new span over the bytes within the supplied range of positions within this span. [`func extracting(unchecked: Range) -> RawSpan`](/documentation/Swift/RawSpan/extracting(unchecked:)-527ri) Constructs a new span over the bytes within the supplied range of positions within this span. [`func isIdentical(to: RawSpan) -> Bool`](/documentation/Swift/RawSpan/isIdentical(to:)) Returns a Boolean value indicating whether two instances refer to the same memory region. [`func isTriviallyIdentical(to: RawSpan) -> Bool`](/documentation/Swift/RawSpan/isTriviallyIdentical(to:)) Returns a Boolean value indicating whether two instances refer to the same memory region. [`func load(fromByteOffset: Int, as: T.Type) -> T`](/documentation/Swift/RawSpan/load(fromByteOffset:as:)) Returns a value constructed from the raw memory at the specified offset. [`func load(fromByteOffset: Int, as: T.Type, ByteOrder) -> T`](/documentation/Swift/RawSpan/load(fromByteOffset:as:_:)) Returns a value constructed from the raw memory at the specified offset. [`func unsafeLoad(fromByteOffset: Int, as: T.Type) -> T`](/documentation/Swift/RawSpan/unsafeLoad(fromByteOffset:as:)) Returns a new instance of the given type, constructed from the raw memory at the specified offset. [`func unsafeLoad(fromUncheckedByteOffset: Int, as: T.Type) -> T`](/documentation/Swift/RawSpan/unsafeLoad(fromUncheckedByteOffset:as:)) Returns a new instance of the given type, constructed from the raw memory at the specified offset. [`func unsafeLoadUnaligned(fromByteOffset: Int, as: T.Type) -> T`](/documentation/Swift/RawSpan/unsafeLoadUnaligned(fromByteOffset:as:)) Returns a new instance of the given type, constructed from the raw memory at the specified offset. [`func unsafeLoadUnaligned(fromUncheckedByteOffset: Int, as: T.Type) -> T`](/documentation/Swift/RawSpan/unsafeLoadUnaligned(fromUncheckedByteOffset:as:)) Returns a new instance of the given type, constructed from the raw memory at the specified offset. [`func withUnsafeBytes((UnsafeRawBufferPointer) throws(E) -> Result) throws(E) -> Result`](/documentation/Swift/RawSpan/withUnsafeBytes(_:)) Calls the given closure with a pointer to the underlying bytes of the viewed contiguous storage. ### Subscripts [`subscript(Int) -> UInt8`](/documentation/Swift/RawSpan/subscript(_:)) Accesses the byte at the specified offset in the span. [`subscript(unchecked _: Int) -> UInt8`](/documentation/Swift/RawSpan/subscript(unchecked:)) Accesses the byte at the specified offset in the span. ### Default Implementations [Iterable Implementations](/documentation/Swift/RawSpan/Iterable-Implementations) ## Relationships ### Conforms To [`Sendable`](/documentation/Swift/Sendable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Iterable`](/documentation/Swift/Iterable) [`ContiguousBytes`](/documentation/Foundation/ContiguousBytes) [`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable) --- 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)