Extended Attributes

Extended Attributes (EA) are a property of directories as well as of files.

Implementation depends on underlying file systems.

Functions

• DosOpen2 for adding EAs to new or existing files
• DosMkDir2 for adding EAs to new directories
• DosQFileInfo, DosQPathInfo to read EAs
• DosFindFirst, DosFindNext to search for files with specific EAs

Standard Extended Attributes

Predefined file types

Assembler Code BASIC Code Binary Data Bitmap C Code COBOL Code DOS Command File Dynamic Link Library Executable FORTRAN Code Icon Library Metafile Pascal Code Plain Text Resource File

.TYPE

type of files (ASCII)

.KEYPHRASES

text key phrases (ASCII)

.SUBJECT

brief summary of content (ASCII single-value)

.COMMENTS

Notes (multi-value)

.HISTORY

file modification (ASCII)

.VERSION

version number (ASCII or binary)

.ICON

binary icon data

.ASSOCTABLE

association

.HPFSNAME

long name

Usage

REXX interpreter

REXX.METACONTROL
REXX.PROGRAMDATA

System Editor

.TYPE

Multimedia Presentation Manager/2

.MMPREF_MMAUDIO
.MMPREF_MMIMAGE
.POSTER

Workplace Shell

.CLASSINFO
.ICON
.ICONPOS
.LONGNAME
.TYPE

Articles

• Roger Orr: Extended Attributes - what are they and how can you use them ? - (May 1993)
• Björn Fahller: Encapsulating Extended Attributes Part 1 (May 1996), Part 2 (Jun 1996)

Links

• Implementation of extended attributes on the FAT file system (Bob Eager)