fixed bug in needing yy_cp for -Cf w/ backing up

1 files changed, 4 insertions, 2 deletions

diff --git a/gen.c b/gen.c
index 192b0dd..aea8d0e 100644
--- a/gen.c
+++ b/gen.c
@@ -668,8 +668,10 @@ void gen_NUL_trans()
 	 */
 	int need_backing_up = (num_backing_up > 0 && ! reject);
 
-	if ( need_backing_up && ! nultrans )
-		/* We'll need yy_cp lying around for the gen_backing_up(). */
+	if ( need_backing_up && (! nultrans || fullspd || fulltbl) )
+		/* We're going to need yy_cp lying around for the call
+		 * below to gen_backing_up().
+		 */
 		indent_puts( "register char *yy_cp = yy_c_buf_p;" );
 
 	outc( '\n' );