sane-dll(5)

1sane-dll(5)              SANE Scanner Access Now Easy              sane-dll(5)
2
3
4

NAME

6       sane-dll - SANE dynamic backend loader
7

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/lib*/sane and adding an entry to the dll.conf con‐
16       figuration file.  In other words, no applications need to  be  modified
17       or recompiled to add support for new devices.
18

DEVICE NAMES

20       This backend expects device names of the form:
21
22              backend:device
23
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).
30

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:
36
37              net
38              # this is a comment
39              pnm
40              mustek
41
42       Note  that  backends that were pre-loaded when building this library do
43       not have to be listed in this configuration file.  That is, if a  back‐
44       end was preloaded, then that backend will always be present, regardless
45       of whether it's listed in the configuration file or not.
46
47       The list of preloaded backends is determined by macro PRELOADABLE_BACK‐
48       ENDS  in file backend/Makefile.in of the SANE source code distribution.
49       After changing the value of this macro, it is necessary to reconfigure,
50       rebuild, and reinstall SANE for the change to take effect.
51
52       Aliases  are  defined  in  the config file dll.aliases.  It can contain
53       entries of the form
54
55              alias SomeName SaneDeviceName
56              alias "Some Name" SaneDeviceName
57              hide SaneDeviceName
58
59       For example:
60
61
62              alias Epson net:somehost:epson:/dev/sgX
63              alias "Siemens ST400" st400:/dev/sgY
64              hide net:somehost:pnm:0
65              hide net:somehost:pnm:1
66              alias "Read from file" pnm:0
67              hide pnm:1
68
69       Aliased device names are automatically hidden.
70
71       The idea is that users don't have to deal with complicated device names
72       (especially  for networked devices), and to hide other exported devices
73       which might confuse them. Note  that  a  hidden  device  can  still  be
74       accessed  if  the  device  name is known, it just doesn't appear on the
75       list.
76
77

FILES

79       /etc/sane.d/dll.aliases
80              The list of aliased or hidden backends.
81
82       /etc/sane.d/dll.conf
83              The  backend  configuration  file  (see  also   description   of
84              SANE_CONFIG_DIR below).
85
86       /usr/lib*/sane/libsane-dll.a
87              The static library implementing this backend.
88
89       /usr/lib*/sane/libsane-dll.so
90              The shared library implementing this backend (present on systems
91              that support dynamic loading).
92

ENVIRONMENT

94       SANE_CONFIG_DIR
95              This environment variable specifies the list of directories that
96              may contain the configuration file.  Under UNIX, the directories
97              are separated by a colon (`:'), under OS/2, they  are  separated
98              by a semi-colon (`;').  If this variable is not set, the config‐
99              uration file is searched in two default directories: first,  the
100              current working directory (".") and then in /etc/sane.d.  If the
101              value of the environment variable ends with the directory  sepa‐
102              rator character, then the default directories are searched after
103              the explicitly  specified  directories.   For  example,  setting
104              SANE_CONFIG_DIR  to  "/tmp/config:"  would result in directories
105              "tmp/config", ".", and "/etc/sane.d"  being  searched  (in  this
106              order).
107
108       SANE_DEBUG_DLL
109              If  the  library  was  compiled with debug support enabled, this
110              environment variable controls the debug level for this  backend.
111              E.g.,  a  value  of 128 requests all debug output to be printed.
112              Smaller levels reduce verbosity.
113
114              Value  Description
115              0      print severe errors only
116              1      print normal errors and important messages
117              2      print normal messages
118              3      print debugging messages
119              4      print everything
120
121              Example: export SANE_DEBUG_DLL=3
122
123
124

AUTHOR

130       David Mosberger
131
132
133
134sane-backends 1.0.18              4 Dec 2002                       sane-dll(5)