diff --git a/crypto/x509v3/v3_genn.c b/crypto/x509v3/v3_genn.c
index 4dc836175a..363f2d32d5 100644
--- a/crypto/x509v3/v3_genn.c
+++ b/crypto/x509v3/v3_genn.c
@@ -102,8 +102,8 @@ IMPLEMENT_ASN1_FUNCTIONS(GENERAL_NAMES)
 
 GENERAL_NAME *GENERAL_NAME_dup(GENERAL_NAME *a)
 	{
-	return (GENERAL_NAME *) ASN1_dup((int (*)()) i2d_GENERAL_NAME,
-					 (char *(*)()) d2i_GENERAL_NAME,
+	return (GENERAL_NAME *) ASN1_dup((i2d_of_void *) i2d_GENERAL_NAME,
+					 (d2i_of_void *) d2i_GENERAL_NAME,
 					 (char *) a);
 	}