sane-dll

sane-dll(5) SANE Scanner Access Now Easy sane-dll(5)

NAME

   sane-dll - SANE dynamic backend loader

DESCRIPTION

   The  sane-dll  library implements a SANE (Scanner Access Now Easy) backend that provides access to an arbitrary number of other SANE backends.  These backends may either be pre-loaded
   at the time the sane-dll library is built or, on systems that support dynamic loading of shared libraries, the backends may be loaded at runtime.  In the latter case,  adding  support
   for  a new backend simply involves installing the relevant library in /usr/lib/x86_64-linux-gnu/sane and adding an entry to the dll.conf configuration file.  In other words, no appli
   cations need to be modified or recompiled to add support for new devices.

DEVICE NAMES

   This backend expects device names of the form:

          backend:device

   Where backend is the name of the backend and device is the name of the device in this backend that should be addressed.  If the device name does not contain a colon (:), then the  en
   tire  string  is  treated  as  the device string for the default backend.  The default backend is the backend listed last in the configuration file (see below) or the first pre-loaded
   backend (if any).

CONFIGURATION

   The contents of the dll.conf file is a list of backend names that may be loaded dynamically upon demand.  Empty lines are ignored, also everything after a hash mark (#). A sample con‐
   figuration file is shown below:

          net
          # this is a comment
          pnm
          mustek

   It is also possible to add a file in /etc/sane.d/dll.d that contains the list of backends to be added. Backends mentioned in a file included in this directory will be added before any
   backends listed in dll.conf.  Files in /etc/sane.d/dll.d can be freely named. They shall follow the format conventions as apply for dll.conf.

   Note that backends that were pre-loaded when building this library do not have to be listed in this configuration file.  That is, if a backend was preloaded, then  that  backend  will
   always be present, regardless of whether it's listed in the configuration file or not.

   The  list  of preloaded backends is determined by macro PRELOADABLE_BACKENDS in file backend/Makefile.in of the SANE source code distribution.  After changing the value of this macro,
   it is necessary to reconfigure, rebuild, and reinstall SANE for the change to take effect.

   Aliases are defined in the config file dll.aliases.  It can contain entries of the form

          alias SomeName SaneDeviceName
          alias "Some Name" SaneDeviceName
          hide SaneDeviceName

   For example:

          alias Epson net:somehost:epson:/dev/sgX
          alias "Siemens ST400" st400:/dev/sgY
          hide net:somehost:pnm:0
          hide net:somehost:pnm:1
          alias "Read from file" pnm:0
          hide pnm:1

   Aliased device names are automatically hidden.

   The idea is that users don't have to deal with complicated device names (especially for networked devices), and to hide other exported devices which might confuse them.  Note  that  a
   hidden device can still be accessed if the device name is known, it just doesn't appear on the list.

FILES

   /etc/sane.d/dll.aliases
          The list of aliased or hidden backends.

   /etc/sane.d/dll.conf
          The backend configuration file (see also description of SANE_CONFIG_DIR below).

   /usr/lib/x86_64-linux-gnu/sane/libsane-dll.a
          The static library implementing this backend.

   /usr/lib/x86_64-linux-gnu/sane/libsane-dll.so
          The shared library implementing this backend (present on systems that support dynamic loading).

ENVIRONMENT

   SANE_CONFIG_DIR
          This  environment  variable  specifies  the list of directories that may contain the configuration file.  On *NIX systems, the directories are separated by a colon (`:'), under
          OS/2, they are separated by a semi-colon (`;').  If this variable is not set, the configuration file is searched in two default directories: first, the current  working  direc
          tory  (".")  and then in /etc/sane.d.  If the value of the environment variable ends with the directory separator character, then the default directories are searched after the
          explicitly specified directories.  For example, setting SANE_CONFIG_DIR to "/tmp/config:" would result in directories tmp/config, ., and /etc/sane.d being searched (in this or
          der).

   SANE_DEBUG_DLL
          If the library was compiled with debug support enabled, this environment variable controls the debug level for this backend.  E.g., a value of 128 requests all debug output  to
          be printed.  Smaller levels reduce verbosity.

          Value  Description
          0      print severe errors only
          1      print normal errors and important messages
          2      print normal messages
          3      print debugging messages
          4      print everything

          Example: export SANE_DEBUG_DLL=3

SEE ALSO

   sane(7), scanimage(1), sane-"backendname"(5)

AUTHOR

   David Mosberger

                                                                                      13 Jul 2008                                                                              sane-dll(5)