diff --git a/src/platform/nm-platform.c b/src/platform/nm-platform.c
index 2b554cb4b9..7535958c7c 100644
--- a/src/platform/nm-platform.c
+++ b/src/platform/nm-platform.c
@@ -1322,7 +1322,7 @@ nm_platform_link_get_ifindex (NMPlatform *self, const char *name)
 }
 
 const char *
-nm_platform_if_indextoname (NMPlatform *self, int ifindex, char *out_ifname/* of size IFNAMSIZ */)
+nm_platform_if_indextoname (NMPlatform *self, int ifindex, char out_ifname[static 16 /* IFNAMSIZ */])
 {
 	_CHECK_SELF_NETNS (self, klass, netns, FALSE);
 
diff --git a/src/platform/nm-platform.h b/src/platform/nm-platform.h
index 56788c182e..7edaaf58e3 100644
--- a/src/platform/nm-platform.h
+++ b/src/platform/nm-platform.h
@@ -1350,7 +1350,8 @@ int nm_platform_sysctl_ip_conf_get_rp_filter_ipv4 (NMPlatform *platform,
                                                    gboolean consider_all,
                                                    gboolean *out_due_to_all);
 
-const char *nm_platform_if_indextoname (NMPlatform *self, int ifindex, char *out_ifname/* of size IFNAMSIZ */);
+const char *nm_platform_if_indextoname (NMPlatform *self, int ifindex,
+                                        char out_ifname[static 16 /* IFNAMSIZ */]);
 int nm_platform_if_nametoindex (NMPlatform *self, const char *ifname);
 
 const NMPObject *nm_platform_link_get_obj (NMPlatform *self,