# Byte-Order Utilities ## Overview When handling binary data transmitted or shared across platforms, you need be concerned with how each platform stores numerical values. A platform stores values either in big-endian or little-endian format. On big-endian machines, such as PowerPC machines, values are stored with the most-significant bytes first in memory; on little-endian machines, such as Pentium machines, values are stored with the least-significant bytes first. A multibyte value transmitted to a platform with a different format will be misinterpreted if it is not converted properly by one of the computers. You identify the native format of the current platform using the [`CFByteOrderGetCurrent()`](/documentation/CoreFoundation/CFByteOrderGetCurrent()) function. Use functions such as [`CFSwapInt32BigToHost(_:)`](/documentation/CoreFoundation/CFSwapInt32BigToHost(_:)) and [`CFConvertFloat32HostToSwapped(_:)`](/documentation/CoreFoundation/CFConvertFloat32HostToSwapped(_:)) to convert values between different byte order formats. ## Topics ### Core Foundation Byte Order Utilities Miscellaneous Functions [`CFByteOrderGetCurrent()`](/documentation/CoreFoundation/CFByteOrderGetCurrent()) Returns the byte order of the current computer. [`CFConvertDoubleHostToSwapped(_:)`](/documentation/CoreFoundation/CFConvertDoubleHostToSwapped(_:)) Converts a 64-bit double from the host’s native byte order to a platform-independent format. [`CFConvertDoubleSwappedToHost(_:)`](/documentation/CoreFoundation/CFConvertDoubleSwappedToHost(_:)) Converts a 64-bit double from a platform-independent format to the host’s native byte order. [`CFConvertFloat32HostToSwapped(_:)`](/documentation/CoreFoundation/CFConvertFloat32HostToSwapped(_:)) Converts a 32-bit float from the host’s native byte order to a platform-independent format. [`CFConvertFloat32SwappedToHost(_:)`](/documentation/CoreFoundation/CFConvertFloat32SwappedToHost(_:)) Converts a 32-bit float from a platform-independent format to the host’s native byte order. [`CFConvertFloat64HostToSwapped(_:)`](/documentation/CoreFoundation/CFConvertFloat64HostToSwapped(_:)) Converts a 64-bit float from the host’s native byte order to a platform-independent format. [`CFConvertFloat64SwappedToHost(_:)`](/documentation/CoreFoundation/CFConvertFloat64SwappedToHost(_:)) Converts a 64-bit float from a platform-independent format to the host’s native byte order. [`CFConvertFloatHostToSwapped(_:)`](/documentation/CoreFoundation/CFConvertFloatHostToSwapped(_:)) Converts a 32-bit float from the host’s native byte order to a platform-independent format. [`CFConvertFloatSwappedToHost(_:)`](/documentation/CoreFoundation/CFConvertFloatSwappedToHost(_:)) Converts a 32-bit float from a platform-independent format to the host’s native byte order. [`CFSwapInt16(_:)`](/documentation/CoreFoundation/CFSwapInt16(_:)) Swaps the bytes of a 16-bit integer. [`CFSwapInt16BigToHost(_:)`](/documentation/CoreFoundation/CFSwapInt16BigToHost(_:)) Converts a 16-bit integer from big-endian format to the host’s native byte order. [`CFSwapInt16HostToBig(_:)`](/documentation/CoreFoundation/CFSwapInt16HostToBig(_:)) Converts a 16-bit integer from the host’s native byte order to big-endian format. [`CFSwapInt16HostToLittle(_:)`](/documentation/CoreFoundation/CFSwapInt16HostToLittle(_:)) Converts a 16-bit integer from the host’s native byte order to little-endian format. [`CFSwapInt16LittleToHost(_:)`](/documentation/CoreFoundation/CFSwapInt16LittleToHost(_:)) Converts a 16-bit integer from little-endian format to the host’s native byte order. [`CFSwapInt32(_:)`](/documentation/CoreFoundation/CFSwapInt32(_:)) Swaps the bytes of a 32-bit integer. [`CFSwapInt32BigToHost(_:)`](/documentation/CoreFoundation/CFSwapInt32BigToHost(_:)) Converts a 32-bit integer from big-endian format to the host’s native byte order. [`CFSwapInt32HostToBig(_:)`](/documentation/CoreFoundation/CFSwapInt32HostToBig(_:)) Converts a 32-bit integer from the host’s native byte order to big-endian format. [`CFSwapInt32HostToLittle(_:)`](/documentation/CoreFoundation/CFSwapInt32HostToLittle(_:)) Converts a 32-bit integer from the host’s native byte order to little-endian format. [`CFSwapInt32LittleToHost(_:)`](/documentation/CoreFoundation/CFSwapInt32LittleToHost(_:)) Converts a 32-bit integer from little-endian format to the host’s native byte order. [`CFSwapInt64(_:)`](/documentation/CoreFoundation/CFSwapInt64(_:)) Swaps the bytes of a 64-bit integer. [`CFSwapInt64BigToHost(_:)`](/documentation/CoreFoundation/CFSwapInt64BigToHost(_:)) Converts a 64-bit integer from big-endian format to the host’s native byte order. [`CFSwapInt64HostToBig(_:)`](/documentation/CoreFoundation/CFSwapInt64HostToBig(_:)) Converts a 64-bit integer from the host’s native byte order to big-endian format. [`CFSwapInt64HostToLittle(_:)`](/documentation/CoreFoundation/CFSwapInt64HostToLittle(_:)) Converts a 64-bit integer from the host’s native byte order to little-endian format. [`CFSwapInt64LittleToHost(_:)`](/documentation/CoreFoundation/CFSwapInt64LittleToHost(_:)) Converts a 64-bit integer from little-endian format to the host’s native byte order. ### Data Types [`CFSwappedFloat32`](/documentation/CoreFoundation/CFSwappedFloat32) Structure holding a 32-bit float value in a platform-independentbyte order. [`CFSwappedFloat64`](/documentation/CoreFoundation/CFSwappedFloat64) Structure holding a 64-bit float value in a platform-independentbyte order. ### Constants [`CFByteOrder`](/documentation/CoreFoundation/CFByteOrder) Flags that identify byte order. ## See Also [Memory Management Programming Guide for Core Foundation](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/CFMemoryMgmt.html#//apple_ref/doc/uid/10000127i) --- 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)