sane-dll(5)

1sane-dll(5)              SANE Scanner Access Now Easy              sane-dll(5)
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NAME

6       sane-dll - SANE dynamic backend loader
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DESCRIPTION

9       The  sane-dll library implements a SANE (Scanner Access Now Easy) back‐
10       end that provides access to an arbitrary number of other SANE backends.
11       These  backends  may  either  be  pre-loaded  at  the time the sane-dll
12       library is built or, on systems that support dynamic loading of  shared
13       libraries,  the backends may be loaded at runtime.  In the latter case,
14       adding support for a new backend simply involves installing  the  rele‐
15       vant  library  in  /usr/lib64/sane  and adding an entry to the dll.conf
16       configuration file.  In other words, no applications need to  be  modi‐
17       fied or recompiled to add support for new devices.
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DEVICE NAMES

20       This backend expects device names of the form:
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22              backend:device
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24       Where  backend is the name of the backend and device is the name of the
25       device in this backend that should be addressed.  If  the  device  name
26       does  not contain a colon (:), then the entire string is treated as the
27       device string for the default backend.   The  default  backend  is  the
28       backend  listed last in the configuration file (see below) or the first
29       pre-loaded backend (if any).
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CONFIGURATION

32       The contents of the dll.conf file is a list of backend names  that  may
33       be  loaded  dynamically  upon  demand.   Empty  lines are ignored, also
34       everything after a hash mark (#). A sample configuration file is  shown
35       below:
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37              net
38              # this is a comment
39              pnm
40              mustek
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42       It  is  also  possible to add a file in /etc/sane.d/dll.d that contains
43       the list of backends to be added. Backends mentioned in a file included
44       in this directory will be added before any backends listed in dll.conf.
45       Files in /etc/sane.d/dll.d can be freely named. They shall  follow  the
46       format conventions as apply for dll.conf.
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49       Note  that  backends that were pre-loaded when building this library do
50       not have to be listed in this configuration file.  That is, if a  back‐
51       end was preloaded, then that backend will always be present, regardless
52       of whether it's listed in the configuration file or not.
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54       The list of preloaded backends is determined by macro PRELOADABLE_BACK‐
55       ENDS  in file backend/Makefile.in of the SANE source code distribution.
56       After changing the value of this macro, it is necessary to reconfigure,
57       rebuild, and reinstall SANE for the change to take effect.
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59       Aliases  are  defined  in  the config file dll.aliases.  It can contain
60       entries of the form
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62              alias SomeName SaneDeviceName
63              alias "Some Name" SaneDeviceName
64              hide SaneDeviceName
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66       For example:
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69              alias Epson net:somehost:epson:/dev/sgX
70              alias "Siemens ST400" st400:/dev/sgY
71              hide net:somehost:pnm:0
72              hide net:somehost:pnm:1
73              alias "Read from file" pnm:0
74              hide pnm:1
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76       Aliased device names are automatically hidden.
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78       The idea is that users don't have to deal with complicated device names
79       (especially  for networked devices), and to hide other exported devices
80       which might confuse them. Note  that  a  hidden  device  can  still  be
81       accessed  if  the  device  name is known, it just doesn't appear on the
82       list.
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FILES

86       /etc/sane.d/dll.aliases
87              The list of aliased or hidden backends.
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89       /etc/sane.d/dll.conf
90              The  backend  configuration  file  (see  also   description   of
91              SANE_CONFIG_DIR below).
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93       /usr/lib64/sane/libsane-dll.a
94              The static library implementing this backend.
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96       /usr/lib64/sane/libsane-dll.so
97              The shared library implementing this backend (present on systems
98              that support dynamic loading).
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ENVIRONMENT

101       SANE_CONFIG_DIR
102              This environment variable specifies the list of directories that
103              may contain the configuration file.  Under UNIX, the directories
104              are separated by a colon (`:'), under OS/2, they  are  separated
105              by a semi-colon (`;').  If this variable is not set, the config‐
106              uration file is searched in two default directories: first,  the
107              current working directory (".") and then in /etc/sane.d.  If the
108              value of the environment variable ends with the directory  sepa‐
109              rator character, then the default directories are searched after
110              the explicitly  specified  directories.   For  example,  setting
111              SANE_CONFIG_DIR  to  "/tmp/config:"  would result in directories
112              "tmp/config", ".", and "/etc/sane.d"  being  searched  (in  this
113              order).
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115       SANE_DEBUG_DLL
116              If  the  library  was  compiled with debug support enabled, this
117              environment variable controls the debug level for this  backend.
118              E.g.,  a  value  of 128 requests all debug output to be printed.
119              Smaller levels reduce verbosity.
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121              Value  Description
122              0      print severe errors only
123              1      print normal errors and important messages
124              2      print normal messages
125              3      print debugging messages
126              4      print everything
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128              Example: export SANE_DEBUG_DLL=3
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AUTHOR

137       David Mosberger
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141                                  13 Jul 2008                      sane-dll(5)