This Technical Note tells you what to watch out for in Finder 6.0.
When the Finder looks for an icon it uses the first match it finds. When more than one icon would match, the order is important.
Some icons are built right into the Finder's resource fork -- those are always searched last. Other than that, the Finder searches in device-number order (for example, icons on device number $0001, the boot device, override icons on other devices).
On each disk, icons in Desktop files override icons in old-style icon files. Among old-style icon files in the same Icons folder, each icon file overrides subsequent (as returned by GetDirEntry) files in the same directory. Within an icons file, earlier icons override later icons.
If you create a "generic" icon that matches a broad class of files -- for example, all files of a particular file type -- you have to be very careful where you put that icon. A generic icon in any file's rBundle will wind up in a Desktop file, where it will override some old-style icon files (or all of them, if the Desktop file is on the boot disk).
There's really no good place for a custom generic icon. (Well, the Finder's resource fork would be a good place, but we recommend not messing with that.) A halfway-good place is in old-style icons folders, at the end, on the highest-numbered convenient device (for example, your third hard drive partition of three).
Note that the 6.0 Finder's matching order for old-style icons is more or less the reverse of what it was in previous versions.
When an icon matches by filename and has a leading wildcard, the match always fails if there are any lowercase characters in the string. For example, "*.TXT" is fine, but "*.Txt" never matches.
Also, a leading wildcard matches one or more characters, instead of (as intended) zero or more characters. "*ICONS" matches "MyIcons" and "Other.Icons", but not "Icons". You can usually work around this by omitting the character after the wildcards: "*CONS" matches all three.
These notes apply both to old-style icon files and to new matchFilename structures.
The System 6.0 Finder Documentation shows one of the words in the rRectList(1) resource as the default choice for the Shut Down dialog. Actually, the default is not configurable, and this word in the resource should remain zero. Utilities can customize the Finder's "Shut Down..." command by accepting the finderSaysMItemSelected request.
This and all of the other Apple II Technical Notes have been converted to HTML by Aaron Heiss as a public service to the Apple II community, with permission by Apple Computer, Inc. Any and all trademarks, registered and otherwise, are properties of their owners.