tdb2: actually implement tdb_error().

[ccan] / ccan / tdb2 / doc / TDB1_porting.txt

diff --git a/ccan/tdb2/doc/TDB1_porting.txt b/ccan/tdb2/doc/TDB1_porting.txt
index b56a426ed4cfd11548afaa0786b0c78cb2a73d0d..90ba2497382d456e285ec6990c5eb86177dbe812 100644 (file)
--- a/ccan/tdb2/doc/TDB1_porting.txt
+++ b/ccan/tdb2/doc/TDB1_porting.txt
@@ -1,8 +1,13 @@
 Interface differences between TDB1 and TDB2.
 
+- tdb2 uses 'struct tdb_data', tdb1 uses 'struct TDB_DATA'.  Use the
+  TDB_DATA typedef if you want portability between the two.
+
 - tdb2 functions return 0 on success, and a negative error on failure,
-  whereas tdb1 functions returned 0 on success, and -1 on failure.  tdb1
-  then used tdb_error() to determine the error.
+  whereas tdb1 functions returned 0 on success, and -1 on failure.
+  tdb1 then used tdb_error() to determine the error; this is also
+  supported in tdb2 to ease backwards compatibility, though the other
+  form is preferred.
 
 - tdb2's tdb_fetch() returns an error, tdb1's returned the data directly
   (or tdb_null, and you were supposed to check tdb_error() to find out why).
@@ -27,3 +32,13 @@ Interface differences between TDB1 and TDB2.
 - tdb2 provides tdb_deq() for comparing two struct tdb_data.
 
 - tdb2's tdb_name() returns a copy of the name even for TDB_INTERNAL dbs.
+
+- tdb2 does not need tdb_reopen() or tdb_reopen_all().  If you call
+  fork() after during certain operations the child should close the
+  tdb, or complete the operations before continuing to use the tdb:
+
+       tdb_transaction_start(): child must tdb_transaction_cancel()
+       tdb_lockall(): child must call tdb_unlockall()
+       tdb_lockall_read(): child must call tdb_unlockall_read()
+       tdb_chainlock(): child must call tdb_chainunlock()
+       tdb_parse() callback: child must return from tdb_parse()