Core Endian Reference provides routines for converting data between big endian and little endian format. These routines are useful for developers who write code that must compile for multiple architectures, including:
Macintosh developers who want to produce a universal binary.
QuickTime developers who want their code to run in Windows as well as in macOS.
Both QuickTime and Macintosh developers can use this API to handle reading or writing data to a file or network packet.
Macintosh developers can use this API to create and install callbacks that are invoked by macOS automatically when your application:
reads and writes custom resource data
sends or receives custom Apple events
reads and writes custom pasteboard data
The functions in this API are designed to do nothing when the target runtime is already in the desired format.
For more information see:
Universal Binary Programming Guidelines, Second Edition
QuickTime API Reference