diff --git a/ref-filter.c b/ref-filter.c
index aa260bfd09..606f638ab1 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -1210,10 +1210,10 @@ static void grab_person(const char *who, struct atom_value *val, int deref, void
 }
 
 static void find_subpos(const char *buf,
-			const char **sub, unsigned long *sublen,
-			const char **body, unsigned long *bodylen,
-			unsigned long *nonsiglen,
-			const char **sig, unsigned long *siglen)
+			const char **sub, size_t *sublen,
+			const char **body, size_t *bodylen,
+			size_t *nonsiglen,
+			const char **sig, size_t *siglen)
 {
 	const char *eol;
 	/* skip past header until we hit empty line */
@@ -1285,7 +1285,7 @@ static void grab_sub_body_contents(struct atom_value *val, int deref, void *buf)
 {
 	int i;
 	const char *subpos = NULL, *bodypos = NULL, *sigpos = NULL;
-	unsigned long sublen = 0, bodylen = 0, nonsiglen = 0, siglen = 0;
+	size_t sublen = 0, bodylen = 0, nonsiglen = 0, siglen = 0;
 
 	for (i = 0; i < used_atom_cnt; i++) {
 		struct used_atom *atom = &used_atom[i];