NAME

proplist - The storing, parsing, and retrieving of Extended File Attributes

DESCRIPTION

DEC OSF/1 supports the storing, parsing, and retrieving of Extended File Attributes.  An Extended File Attribute is a name and value pair that is contained in a variable-sized structure called a Property List.  A Property List is part of a file’s metadata and can contain abstract name and value pairs (Extended File Attributes) that can be set either by the operating system (for example, ACLs and privileges) or by a user-level application (for example, PC File Attributes). 

Since Extended File Attributes are treated as an extension to a file’s metadata, they are synchronously updated, thereby ensuring consistency.  Note that Extended File Attributes set by user-level applications are treated as opaque and can be virtually anything. 

To ensure that all Property List names are unique, you must register your Property List names with Digital.  Those Property List names with a DEC_ prefix are reserved by Digital. In the case of conflicts, Digital reserves the right to arbitrate the naming conventions of Property Lists.

To register a Property List name, send a request by network mail to file_proplist_admin@zk3.dec.com or write to:

DEC OSF/1 File System Group
ATTN: Property List Administrator
Digital Equipment Corporation
110 Spit Brook Road
Nashua, NH. 03062-2698
M/S ZKO3-3/U14

Several user-level routines, listed in the Related Information section, work together to manipulate Extended File Attributes.  For example, Digital recommends that you use the sizeof_proplist_entry(3) and add_proplist_entry(3) routines to initialize the Extended File Attribute buffer passed to setproplist(3) and fsetproplist(3); and the get_proplist_entry(3) routine to parse the attribute buffer returned by getproplist(3) and fgetproplist(3). 

The format of the Extended File Attributes buffer, the values of the system-wide properties, and the format of the Property List structures are all defined in sys/proplist.h. 

NOTES

Extended File Attributes are supported by the Advanced File System (AdvFS) and the UNIX File System (UFS).  Currently, the Network File System (NFS) does not support Extended File Attributes, so when files migrate over NFS, they loose any Extended File Attributes they may have had. 

The archive utilities (pax, tar, cpio, dump, restore, vdump, and vrestore) support files with Extended File Attributes. However, third-party archive utilities may not support Extended File Attributes and, consequently, if they are used on files with Extended File Attributes, the Extended File Attributes will be lost.

RELATED INFORMATION

Functions: add_proplist_entry(3), delproplist(3), fdelproplist(3), fgetproplist(3), fsetproplist(3), get_proplist_entry(3), getproplist(3), setproplist(3), sizeof_proplist_entry(3). 

Files: libproplist.a, libproplist.so, sys/proplist.h.