diff --git a/lib/libmime/mimeobj.c b/lib/libmime/mimeobj.c
index 656b530fb82..d67571dbfac 100644
--- a/lib/libmime/mimeobj.c
+++ b/lib/libmime/mimeobj.c
@@ -213,7 +213,7 @@ MimeObject_parse_buffer (char *buffer, int32 size, MimeObject *obj)
   return msg_LineBuffer (buffer, size,
 						 &obj->ibuffer, &obj->ibuffer_size, &obj->ibuffer_fp,
 						 TRUE,
-						 ((long (*) (char *, uint32, void *))
+						 ((int32 (*) (char *, uint32, void *))
 						  /* This cast is to turn void into MimeObject */
 						  obj->class->parse_line),
 						 obj);
diff --git a/lib/libmime/mimetext.c b/lib/libmime/mimetext.c
index d249052bf10..e2bcf840f50 100644
--- a/lib/libmime/mimetext.c
+++ b/lib/libmime/mimetext.c
@@ -235,7 +235,7 @@ MimeInlineText_parse_decoded_buffer (char *buf, int32 size, MimeObject *obj)
   return msg_LineBuffer (buf, size,
 						 &obj->ibuffer, &obj->ibuffer_size, &obj->ibuffer_fp,
 						 TRUE,
-						 ((long (*) (char *, uint32, void *))
+						 ((int32 (*) (char *, uint32, void *))
 						  /* This cast is to turn void into MimeObject */
 						  MimeInlineText_rotate_convert_and_parse_line),
 						 obj);