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sane-dll(5) SANE Scanner Access Now Easy sane-dll(5) NAME sane-dll - SANE dynamic backend loader DESCRIPTION The sane-dll library implements a SANE (Scanner Access Now Easy) back- end that provides access to an arbitrary number of other SANE backends. These backends may either be pre-loaded at the time the sane-dll li- brary is built or, on systems that support dynamic loading of shared libraries, the backends may be loaded at runtime. In the latter case, adding support for a new backend simply involves installing the rele- vant library in /usr/local/lib/sane and adding an entry to the dll.conf configuration file. In other words, no applications need to be modi- fied or recompiled to add support for new devices. DEVICE NAMES This backend expects device names of the form: backend:device Where backend is the name of the backend and device is the name of the device in this backend that should be addressed. If the device name does not contain a colon (:), then the entire string is treated as the device string for the default backend. The default backend is the backend listed last in the configuration file (see below) or the first pre-loaded backend (if any). CONFIGURATION The contents of the dll.conf file is a list of backend names that may be loaded dynamically upon demand. Empty lines are ignored, also everything after a hash mark (#). A sample configuration file is shown below: net # this is a comment pnm mustek It is also possible to add a file in /usr/local/etc/sane.d/dll.d that contains the list of backends to be added. Backends mentioned in a file included in this directory will be added before any backends listed in dll.conf. Files in /usr/local/etc/sane.d/dll.d can be freely named. They shall follow the format conventions as apply for dll.conf. Note that backends that were pre-loaded when building this library do not have to be listed in this configuration file. That is, if a back- end was preloaded, then that backend will always be present, regardless of whether it's listed in the configuration file or not. The list of preloaded backends is determined by macro PRELOADABLE_BACK- ENDS in file backend/Makefile.in of the SANE source code distribution. After changing the value of this macro, it is necessary to reconfigure, rebuild, and reinstall SANE for the change to take effect. Aliases are defined in the config file dll.aliases. It can contain en- tries of the form alias SomeName SaneDeviceName alias "Some Name" SaneDeviceName hide SaneDeviceName For example: alias Epson net:somehost:epson:/dev/sgX alias "Siemens ST400" st400:/dev/sgY hide net:somehost:pnm:0 hide net:somehost:pnm:1 alias "Read from file" pnm:0 hide pnm:1 Aliased device names are automatically hidden. The idea is that users don't have to deal with complicated device names (especially for networked devices), and to hide other exported devices which might confuse them. Note that a hidden device can still be ac- cessed if the device name is known, it just doesn't appear on the list. FILES /usr/local/etc/sane.d/dll.aliases The list of aliased or hidden backends. /usr/local/etc/sane.d/dll.conf The backend configuration file (see also description of SANE_CONFIG_DIR below). /usr/local/lib/sane/libsane-dll.a The static library implementing this backend. /usr/local/lib/sane/libsane-dll.so The shared library implementing this backend (present on systems that support dynamic loading). ENVIRONMENT SANE_CONFIG_DIR This environment variable specifies the list of directories that may contain the configuration file. On *NIX systems, the direc- tories are separated by a colon (`:'), under OS/2, they are sep- arated by a semi-colon (`;'). If this variable is not set, the configuration file is searched in two default directories: first, the current working directory (".") and then in /usr/lo- cal/etc/sane.d. If the value of the environment variable ends with the directory separator character, then the default direc- tories are searched after the explicitly specified directories. For example, setting SANE_CONFIG_DIR to "/tmp/config:" would re- sult in directories tmp/config, ., and /usr/local/etc/sane.d be- ing searched (in this order). SANE_DEBUG_DLL If the library was compiled with debug support enabled, this en- vironment variable controls the debug level for this backend. E.g., a value of 128 requests all debug output to be printed. Smaller levels reduce verbosity. Value Description 0 print severe errors only 1 print normal errors and important messages 2 print normal messages 3 print debugging messages 4 print everything Example: export SANE_DEBUG_DLL=3 SEE ALSO sane(7), scanimage(1), sane-"backendname"(5) AUTHOR David Mosberger 13 Jul 2008 sane-dll(5)
NAME | DESCRIPTION | DEVICE NAMES | CONFIGURATION | FILES | ENVIRONMENT | SEE ALSO | AUTHOR
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