Added some hints about what to do to add a new backend to the existing

sane-backends code.

ChangeLog

@@ -5,6 +5,8 @@
 	  doc/descriptions-external/hp3900.desc: Added external hp3900
 	  backend. Moved (possibly) supported scanners from
 	  unsupported.desc. 
+	* doc/backend-writing.c: Added some hints about what to do to add
+	  a new backend to the existing sane-backends code.
 
 2005-12-24  Henning Meier-Geinitz <henning@meier-geinitz.de>
 

doc/backend-writing.txt

@@ -1,4 +1,4 @@
-2005-09-03
+2005-12-27
 
 Here are a few rules and tips that should help writing a
 SANE-conforming backend and including it into the SANE package:
@@ -49,6 +49,18 @@ PROGRAMMING
   is useful to split big backends into several files, the number of .c files
   shouldn't exceed 5-10. Please see the existing backends for examples.
 
+* To add the backend to the existing SANE code, the following must be done at
+  least:
+    - add the backend name to BACKENDS in configure.in (and rerun autoconf)
+    - add any parts of SANE that are used in the backend in
+      backend/Makefile.in. E.g., for the backend "newbackend" that uses
+      sanei_usb code:
+           libsane-newbackend.la: ../sanei/sanei_usb.lo
+      See the lines near the end of Makefile.in for examples.
+    - Add the source code files to the backend/ directories. All file names must
+      start with the backend name (e.g. newbackend.c, newbackend.h and
+      newbackend-usb.c). 
+
 * Please follow the GNU coding standards.  It's clear that the style
   outlined there is nobody's favorite, but it's much easier to
   maintain SANE if everybody follows more or less the same coding