--- a/pop3d.h	Wed Apr 02 14:44:04 2014 +0500
+++ b/pop3d.h	Mon Apr 07 12:28:10 2014 +0500
@@ -104,7 +104,7 @@
 
 struct m_backend {
 	int (*init)(struct mdrop *, size_t *, size_t *);
-	int (*retr)(struct mdrop *, unsigned int, size_t *, size_t *);
+	int (*retr)(struct mdrop *, unsigned int, size_t *, long *);
 	int (*update)(struct mdrop *);
 };