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.
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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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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 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.
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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.
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52 Aliases are defined in the config file dll.aliases. It can contain
53 entries of the form
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55 alias SomeName SaneDeviceName
56 alias "Some Name" SaneDeviceName
57 hide SaneDeviceName
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59 For example:
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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
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69 Aliased device names are automatically hidden.
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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.
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79 /etc/sane.d/dll.aliases
80 The list of aliased or hidden backends.
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82 /etc/sane.d/dll.conf
83 The backend configuration file (see also description of
84 SANE_CONFIG_DIR below).
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86 /usr/lib64/sane/libsane-dll.a
87 The static library implementing this backend.
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89 /usr/lib64/sane/libsane-dll.so
90 The shared library implementing this backend (present on systems
91 that support dynamic loading).
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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).
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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.
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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
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121 Example: export SANE_DEBUG_DLL=3
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126 sane(7), scanimage(1), sane-"backendname"[22m(5)
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130 David Mosberger
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134 13 Jul 2008 sane-dll(5)