Mach-O, short for Mach object file format, is a file format for executables and object code. An executable file format specifies the order in which code and data is loaded into memory, as ordering of code and data in the file.

Mach-O is utilized by systems based on the Mach kernel. NeXTSTEP and Mac OS X are examples of systems that use this format for native executables, libraries and object code. GNU/Hurd, which uses GNU Mach as microkernel, utilizes ELF, and not Mach-O, as its standard binary format.

Binaries are divided into segments. Each segment consists of one or more sections.

External link

• Mach-O File Format Reference (Apple Computer)