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 li‐
12       brary 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

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 ev‐
34       erything 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       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
48
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.
53
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.
58
59       Aliases are defined in the config file dll.aliases.  It can contain en‐
60       tries of the form
61
62              alias SomeName SaneDeviceName
63              alias "Some Name" SaneDeviceName
64              hide SaneDeviceName
65
66       For example:
67
68
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
75
76       Aliased device names are automatically hidden.
77
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  ac‐
81       cessed if the device name is known, it just doesn't appear on the list.
82
83

FILES

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

ENVIRONMENT

100       SANE_CONFIG_DIR
101              This environment variable specifies the list of directories that
102              may contain the configuration file.  On *NIX systems, the direc‐
103              tories are separated by a colon (`:'), under OS/2, they are sep‐
104              arated by a semi-colon (`;').  If this variable is not set,  the
105              configuration  file  is  searched  in  two  default directories:
106              first,  the  current  working  directory  (".")  and   then   in
107              /etc/sane.d.  If the value of the environment variable ends with
108              the directory separator character, then the default  directories
109              are  searched  after  the explicitly specified directories.  For
110              example, setting SANE_CONFIG_DIR to "/tmp/config:" would  result
111              in directories tmp/config, ., and /etc/sane.d being searched (in
112              this order).
113
114       SANE_DEBUG_DLL
115              If the library was compiled with debug support enabled, this en‐
116              vironment  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
120              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
127              Example: export SANE_DEBUG_DLL=3
128
129
130

AUTHOR

136       David Mosberger
137
138
139
140                                  13 Jul 2008                      sane-dll(5)