SYNOPSIS

       #include <blkid/blkid.h>

       cc file.c -lblkid

DESCRIPTION

       The  libblkid  library  is used to identify block devices (disks) as to
       their content (e.g.  filesystem type) as well as extracting  additional
       information  such  as  filesystem  labels/volume  names, unique identi-
       fiers/serial numbers, etc.  A common use is to allow use of LABEL=  and
       UUID= tags instead of hard-coding specific block device names into con-
       figuration files.

       Block  device  information  is  normally   kept   in   a   cache   file
       /etc/blkid.tab  and is verified to still be valid before being returned
       to the user (if the user has read permission on the raw  block  device,
       otherwise  not).   The  cache file also allows unprivileged users (nor-
       mally anyone other than root, or those not  in  the  "disk"  group)  to
       locate devices by label/id.

       In  situations  where  one  is getting information about a single known
       device, it does not impact performance whether the cache is used or not
       (unless  you  are  not able to read the block device directly).  If you
       are dealing with multiple devices use of the  cache  is  highly  recom-
       mended (even if empty) as devices will be scanned at most one time, and
       the on-disk cache will be updated if possible.  There is rarely a  rea-
       son not to use the cache.

       In  some  cases  (modular  kernels), block devices are not even visible
       until after they are accessed the first time, so it  is  critical  that
       there is some way to locate these devices without enumerating only vis-
       ible devices, so the use of the cache file is required in  this  situa-
       tion.

AUTHOR

       libblkid  was  written  by Andreas Dilger for the ext2 filesystem util-
       ties, with input from Ted Ts'o.  The library was  subsequently  heavily
       modified by Ted Ts'o.

FILES

       /etc/blkid.tab
              Caches data extracted from each recognized block device.

AVAILABILITY

       libblkid  is  part  of  the e2fsprogs package since version 1.33 and is
       available from http://e2fsprogs.sourceforge.net.

COPYING

       libblkid is available under the terms of the GNU Library General Public
       License (LGPL), version 2 (or at your discretion any later version).  A
       copy of the LGPL should be included with this library in the file COPY-
       ING.  If not, write to

E2fsprogs version 1.40.3         December 2007                     LIBBLKID(3)