FreeBSD 4.11 manual page repository

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extattr - virtual file system named extended attributes

 

NAME

      extattr - virtual file system named extended attributes
 

SYNOPSIS

      #include <sys/param.h>
      #include <sys/vnode.h>
      #include <sys/extattr.h>
 

DESCRIPTION

      Named extended attributes allow additional meta-data to be associated
      with vnodes representing files and directories.  The semantics of this
      additional data is that of a "name=value" pair, where a name may be
      defined or undefined, and if defined, associated with zero or more bytes
      of arbitrary binary data.  Reads of this data may return specific con‐
      tiguous regions of the meta-data, in the style of VOP_READ(9), but writes
      will replace the entire current "value" associated with a given name.  As
      there are a plethora of file systems with differing extended attributes,
      availability and functionality of these functions may be limited, and
      they should be used with awareness of the underlying semantics of the
      supporting file system.  Authorization schemes for extended attribute
      data may also vary by file system, as well as maximum attribute size, and
      whether or not any or specific new attributes may be defined.
 
      Extended attributes are named using a null-terminated character string.
      Depending on file system semantics, this name may or may not be case-sen‐
      sitive.  Appropriate vnode extended attribute calls are:
      VOP_GETEXTATTR(9) and VOP_SETEXTATTR(9).
      VFS(9), VOP_GETEXTATTR(9), VOP_SETEXTATTR(9)
 

AUTHORS

      This man page was written by Robert Watson.
 

Sections

Based on BSD UNIX
FreeBSD is an advanced operating system for x86 compatible (including Pentium and Athlon), amd64 compatible (including Opteron, Athlon64, and EM64T), UltraSPARC, IA-64, PC-98 and ARM architectures. It is derived from BSD, the version of UNIX developed at the University of California, Berkeley. It is developed and maintained by a large team of individuals. Additional platforms are in various stages of development.