Index: src/sqlite.h.in
==================================================================
--- src/sqlite.h.in
+++ src/sqlite.h.in
@@ -5618,11 +5618,13 @@
 ** column exists.  ^The sqlite3_table_column_metadata() interface returns
 ** SQLITE_ERROR and if the specified column does not exist.
 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
 ** NULL pointer, then this routine simply checks for the existence of the
 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
-** does not.
+** does not.  If the table name parameter T in a call to
+** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
+** undefined behavior.
 **
 ** ^The column is identified by the second, third and fourth parameters to
 ** this function. ^(The second parameter is either the name of the database
 ** (i.e. "main", "temp", or an attached database) containing the specified
 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched