Creator code

A creator code is a mechanism introduced in the classic Mac OS to link a data file to the application program which created it.

Creator codes could be any four-byte value, but were usually chosen so that their ASCII representation formed a word or acronym.

The OS collected this data from the files when they were copied between mediums, thereby building up the list of associations and icons as software was installed onto the machine.

A more obvious advantage of this approach is allowing for double click launching of specialized editors for more complex but common file types, like .csv or .html.

However, beginning with Mac OS X Snow Leopard, creator codes are ignored by the operating system.

The creator code is responsible for linking the file and the program that will launch when the file is double-clicked. This Mac OS window show four files of the same type code ( MP3 ), but with four different creator codes: Audn ( Audion ), hook ( iTunes ), SCPL ( SoundApp ) and NSWa ( Winamp ).