A creator code is a mechanism introduced in pre-OS X versions of the Macintosh operating system to link a data file to the application program which created it. The similar type code held the file type, like "TEXT". Together, the type and creator indicated what application should be used to open a file, similar to (but richer than) the file extensions in other operating systems.
Creator codes are four-byte OSTypes. For example, the creator code of the HyperCard application and its associated "stacks" is WILD. This allows the application to launch and open a file whenever any of its associated files is double-clicked. Creator codes could contain numbers and some special characters. Occasionally they represented inside jokes. For instance, the Marathon computer game had a creator code of 26.2 (the approximate length, in miles, of a marathon) and Marathon 2: Durandal had a creator code of 52.4.
The binding are stored inside the resource fork of the application as BNDL and fref resources. These resources maintained the creator code as well as the association with each type code and icon. 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. Periodically this "desktop database" would become corrupted, and had to be fixed by "rebuilding the desktop database".
The key difference between extensions and Apple's system is that file type and file ownership bindings are kept distinct. This allows files to be written of the same type - TEXT say - by different applications. Although any application can open anyone else's TEXT file, by default, opening the file will open the original application that created it. With the extensions approach, this distinction is lost - all files with a .txt extension will be mapped to a single text editing application of the user's choosing. A more obvious advantage of this approach is specialized editors for more complex but common file types, like .csv.
OS X retains creator codes, but supports extensions as well (However, beginning with OS X 10.6 Snow Leopard, creator codes are ignored by the Operating System.). Creator codes have been internally superseded by Apple's Uniform Type Identifier scheme, which manages application and file type identification as well as type codes, creator codes and file extensions.
Apple's developer documentation states that applications should continue to set type codes and optionally set creator codes. If either already exists, applications should preserve them. Furthermore, creator codes are used in document binding prior to the file extension alone.
Creator codes are not readily accessible for users to manipulate, although they can be viewed and changed with certain software, most notably the OS X command line tools GetFileInfo and SetFile which are installed as part of the developer tools into /Developer/Tools.
Famous quotes containing the words code and/or creator:
“Many people will say to working mothers, in effect, I dont think you can have it all. The phrase for have it all is code for have your cake and eat it too. What these people really mean is that achievement in the workplace has always come at a priceusually a significant personal price; conversely, women who stayed home with their children were seen as having sacrificed a great deal of their own ambition for their families.”
—Anne C. Weisberg (20th century)
“Preach in the name of God. The learned will smile; ask the learned what they have done for their country. The priests will excommunicate you; say to the priests that you know God better than all of them together do, and that between God and His law you have no need of any intermediary. The people will understand you, and repeat with you: We believe in God the Father, who is Intelligence and Love, Creator and Teacher of Humanity. And in this saying you and the People will conquer.”
—Giuseppe Mazzini (18051872)