MDB_CP_COMPACT comments

diff --git a/libraries/liblmdb/mdb.c b/libraries/liblmdb/mdb.c
index e43e8dcf4263a699a368482e4b3297854bcf6c9d..b057829ac5a85f0c58eb4e3b319da5d63d3532f6 100644 (file)
--- a/libraries/liblmdb/mdb.c
+++ b/libraries/liblmdb/mdb.c
@@ -9765,7 +9765,10 @@ typedef struct mdb_copy {
        HANDLE mc_fd;
        int mc_toggle;                  /**< Buffer number in provider */
        int mc_new;                             /**< (0-2 buffers to write) | (#MDB_EOF at end) */
-       volatile int mc_error;  /**< Error code, never cleared if set */
+       /** Error code.  Never cleared if set.  Both threads can set nonzero
+        *      to fail the copy.  Not mutex-protected, LMDB expects atomic int.
+        */
+       volatile int mc_error;
 } mdb_copy;
 
        /** Dedicated writer thread for compacting copy. */
@@ -9850,7 +9853,11 @@ mdb_env_cthr_toggle(mdb_copy *my, int adjust)
        return my->mc_error;
 }
 
-       /** Depth-first tree traversal for compacting copy. */
+       /** Depth-first tree traversal for compacting copy.
+        * @param[in] my control structure.
+        * @param[in,out] pg database root.
+        * @param[in] flags includes #F_DUPDATA if it is a sorted-duplicate sub-DB.
+        */
 static int ESECT
 mdb_env_cwalk(mdb_copy *my, pgno_t *pg, int flags)
 {