Add db2/db1 compatibility question.

diff --git a/FAQ.in b/FAQ.in
index 91acca2..9f92170 100644 (file)
--- a/FAQ.in
+++ b/FAQ.in
@@ -1287,6 +1287,21 @@ suffix `_unlocked', for details check <stdio.h>.  Using `putc_unlocked' etc.
 instead of `putc' should give nearly the same speed with bonnie (bonnie is a
 benchmark program for measuring disk access).
 
+??     Programs compiled with glibc 2.1 can't read db files made with glibc
+       2.0.  What has changed that programs like rpm break?
+
+{AJ} The GNU C library 2.1 uses db2 instead of db1 which was used in version
+2.0.  The internal formats of the actual db files are different.  To convert
+the db files from db1 format to db2 format, you can use the programs
+`db_dump185' and `db_load'.  Alternativly programs can be linked with db1
+using `-ldb1' instead of linking with db2 which uses `-ldb'.  Linking with
+db1 might be preferable if older programs need to access the db file.
+
+db2 supports the old db1 programming interface and also a new programming
+interface.  For compilation with the old API, <db_185.h> has to be included
+(and not <db.h>) and you can link with either `-ldb1' or `-ldb' for either
+of the db formats.
+
 
 ? Miscellaneous