diff --git a/src/include/lwip/if_api.h b/src/include/lwip/if_api.h
index 007cf4d6..39017abd 100644
--- a/src/include/lwip/if_api.h
+++ b/src/include/lwip/if_api.h
@@ -40,8 +40,15 @@
 #define LWIP_HDR_IF_H
 
 #include "lwip/opt.h"
+
+#if LWIP_SOCKET /* don't build if not configured for use in lwipopts.h */
+
 #include "lwip/netif.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define IF_NAMESIZE NETIF_NAMESIZE
 
 char * lwip_if_indextoname(unsigned int ifindex, char *ifname);
@@ -52,4 +59,10 @@ unsigned int lwip_if_nametoindex(const char *ifname);
 #define if_nametoindex(ifname)           lwip_if_nametoindex(ifname)
 #endif /* LWIP_COMPAT_SOCKETS */
 
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_SOCKET */
+
 #endif /* LWIP_HDR_IF_H */