r17771: add a comment explaing the odd cast

(This used to be commit 47e695ed88d364a7d423e804fe5340006ebf7c18)

diff --git a/source4/lib/ldb/ldb_tdb/ldb_index.c b/source4/lib/ldb/ldb_tdb/ldb_index.c
index c6feeaeb42b96f26706f95089d5fbf5cca69598b..b628c31b095d2c19d159310f9c29146e8bd74e32 100644 (file)
--- a/source4/lib/ldb/ldb_tdb/ldb_index.c
+++ b/source4/lib/ldb/ldb_tdb/ldb_index.c
@@ -61,6 +61,12 @@ static int ldb_list_find(const void *needle,
                int r;
 
                test_i = (min_i + max_i) / 2;
+               /* the following cast looks strange, but is
+                correct. The key to understanding it is that base_p
+                is a pointer to an array of pointers, so we have to
+                dereference it after casting to void **. The strange
+                const in the middle gives us the right type of pointer
+                after the dereference  (tridge) */
                r = comp_fn(needle, *(void * const *)(base_p + (size * test_i)));
                if (r == 0) {
                        /* scan back for first element */