sane-dll(5)

sane-dll -- SANE dynamic backend loader

Description

sane-dll implements a SANE (Scanner Access Now Easy) backend that provides access to an arbitrary number of other SANE backends. These backends may either be pre-loaded at the time the sane-dll library 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 relevant library in /usr/local/lib and adding an entry to the dll.conf configuration file. In other words, no applications need to be modified or recompiled to add support for new devices.

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).

dll.conf contains a list of backend names that may be loaded dynamically upon demand. Empty lines and lines starting with a hash (``#'') are ignored. A sample configuration file is shown below: 

   net
   # this is a comment
   pnm
   mustek
Backends that are pre-loaded when building this library do not have to be listed in this configuration file. That is, if a backend is pre-loaded, then that backend will always be present, regardless of whether it is listed in the configuration file or not.

The list of pre-loaded backends is determined by the macro PRELOADABLE_BACKENDS 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.

The SANE_CONFIG_DIR environment variable specifies the list of directories that may contain the configuration file. The directories are separated by a colon (``:''). If this variable is not set, the configuration file is searched in two default directories: firstly, the current working directory (``.'') and then in /usr/local/etc/sane.d. If the value of the environment variable ends with the directory separator character, then the default directories are searched after the explicitly specified directories. For example, setting SANE_CONFIG_DIR to ``/tmp/config:'' would result in directories tmp/config, ``.'', and /usr/local/etc/sane.d being searched (in this order).

The SANE_DEBUG_DLL environment variable controls the debug level for the sane-dc25 backend if the library was compiled with debugging support enabled. A value of 128 requests full debug output; smaller levels reduce verbosity.

Files


/usr/local/etc/sane.d/dll.conf
The backend configuration file (see the description of SANE_CONFIG_DIR).

/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 (pre- sent on systems that support dynamic loading).

Notices

Author is David Mosberger.

References

sane-abaton(5), sane-agfafocus(5), sane-apple(5), saned(1), sane-dc25(5) sane-dmc(5), sane-epson(5), sane-hp(5), sane-microtek(5), sane-microtek2(5), sane-mustek(5) sane-net(5), sane-pint(5), sane-pnm(5), sane-umax(5), scanimage(1), xsane(1), xscanimage(1)
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004