1sane-dll(5) SANE Scanner Access Now Easy sane-dll(5)
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6 sane-dll - SANE dynamic backend loader
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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.
18
20 This backend expects device names of the form:
21 backend:device
23 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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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 net
38 # this is a comment
39 pnm
40 mustek
41 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.
47 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.
53 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.
58 Aliases are defined in the config file dll.aliases. It can contain
60 entries of the form
61 alias SomeName SaneDeviceName
63 alias "Some Name" SaneDeviceName
64 hide SaneDeviceName
65 For example:
67 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
75 Aliased device names are automatically hidden.
77 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.
83
86 /etc/sane.d/dll.aliases
87 The list of aliased or hidden backends.
88 /etc/sane.d/dll.conf
90 The backend configuration file (see also description of
91 SANE_CONFIG_DIR below).
92 /usr/lib64/sane/libsane-dll.a
94 The static library implementing this backend.
95 /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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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 order).
113 SANE_DEBUG_DLL
115 If the library was compiled with debug support enabled, this
116 environment variable controls the debug level for this backend.
117 E.g., a value of 128 requests all debug output to be printed.
118 Smaller levels reduce verbosity.
119 Value Description
121 0 print severe errors only
122 1 print normal errors and important messages
123 2 print normal messages
124 3 print debugging messages
125 4 print everything
126 Example: export SANE_DEBUG_DLL=3
128
132 sane(7), scanimage(1), sane-"backendname"[22m(5)
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136 David Mosberger
137 13 Jul 2008 sane-dll(5)