Compiler masochism compliance.

[exim.git] / src / src / lookups / README

diff --git a/src/src/lookups/README b/src/src/lookups/README
index 7a16b83a286239dcacc92946c1906575a72a78c3..7490f0a27a8ba263a316bd9244611503bc83d267 100644 (file)
--- a/src/src/lookups/README
+++ b/src/src/lookups/README
@@ -1,11 +1,14 @@
-$Cambridge: exim/src/src/lookups/README,v 1.1 2004/10/07 13:10:01 ph10 Exp $
+$Cambridge: exim/src/src/lookups/README,v 1.2 2005/08/01 13:20:28 ph10 Exp $
 
 LOOKUPS
 -------
 
 Each lookup type is implemented by 6 functions, xxx_open(), xxx_check(),
 xxx_find(), xxx_close(), xxx_tidy(), and xxx_quote(), where xxx is the name of
-the lookup type (e.g. lsearch, dbm, or whatever).
+the lookup type (e.g. lsearch, dbm, or whatever). In addition, there is
+a version reporting function used to trace compile-vs-runtime conflicts and
+to help administrators ensure that the modules from the correct build are
+in use by the main binary.
 
 The xxx_check(), xxx_close(), xxx_tidy(), and xxx_quote() functions need not
 exist. There is a table in drtables.c which links the lookup names to the
@@ -26,11 +29,16 @@ key" style, where the key is associated with a "file name".
 For single key lookups, this means that the file name must be an absolute path.
 It is set for lsearch and dbm, but not for NIS, for example.
 
-When a single-key lookup file is opened, the handle returned by the xxx_open()
-function is saved, along with the file name and lookup type, in a tree. The
-xxx_close() function is not called when the first lookup is completed. If there
-are subsequent lookups of the same type that quote the same file name,
-xxx_open() isn't called; instead the cached handle is re-used.
+  lookup_absfilequery
+
+This is a query-style lookup that must start with an absolute file name. For
+example, the sqlite lookup is of this type.
+
+When a single-key or absfilequery lookup file is opened, the handle returned by
+the xxx_open() function is saved, along with the file name and lookup type, in
+a tree. The xxx_close() function is not called when the first lookup is
+completed. If there are subsequent lookups of the same type that quote the same
+file name, xxx_open() isn't called; instead the cached handle is re-used.
 
 Exim calls the function search_tidyup() at strategic points in its processing
 (e.g. after all routing and directing has been done) and this function walks
@@ -153,4 +161,14 @@ needed, it can return its single argument, which is a uschar *. This function
 does NOT use the POOL_SEARCH store, because it's usually never called from any
 lookup code.
 
+xxx_report_version()
+--------------------
+
+This is called to report diagnostic information to a file stream.
+Typically it would report both compile-time and run-time version information.
+The arguments are:
+
+  FILE *stream    where to fprintf() the data to
+
+
 ****