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.
+a tree. Traditionally, lookup_querystyle does not use this (just returning a
+dummy value, and doing the "open" work in the xxx_find() routine); but this is
+not enforced by the framework.
+
+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
uschar **errmsg where to put an error message if there is a problem
The yield of xxx_open() is a void * value representing the open file or
-database. For real files is is normally the FILE or DBM value. For other
+database. For real files it is normally the FILE or DBM value. For other
kinds of lookup, if there is no natural value to use, (-1) is recommended.
The value should not be NULL (or 0) as that is taken to indicate failure of
the xxx_open() function. For single-key lookups, the handle is cached along
If set to a nonzero number of seconds, the cached value
becomes unusable after this time. Currently the dnsdb
lookup uses this to support the TTL value.
+ uschar *opts options, a comma-separated list of tagged values for
+ modifying the search operation
Even though the key is zero-terminated, the length is passed because in the
common case it has been computed already and is often needed.
does NOT use the POOL_SEARCH store, because it's usually never called from any
lookup code.
-xxx_report_version()
+xxx_version_report()
--------------------
This is called to report diagnostic information to a file stream.