Included patch #5448: include '#ifdef __cplusplus \ extern "C" {' in all header files. Now you can write your application using the lwIP stack in C++ and simply #include the core files. Note I have left out the netif/ppp/*h header files for now, since I don't know which files are included by applications and which are for internal use only.

src/include/netif/etharp.h

@@ -41,6 +41,10 @@
 #include "lwip/netif.h"
 #include "lwip/ip.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef ETH_PAD_SIZE
 #define ETH_PAD_SIZE 0
 #endif
@@ -136,4 +140,8 @@ err_t etharp_output(struct netif *netif, struct ip_addr *ipaddr,
 err_t etharp_query(struct netif *netif, struct ip_addr *ipaddr, struct pbuf *q);
 err_t etharp_request(struct netif *netif, struct ip_addr *ipaddr);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __NETIF_ARP_H__ */

src/include/netif/loopif.h

@@ -35,10 +35,18 @@
 #include "lwip/netif.h"
 #include "lwip/err.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if !LWIP_LOOPIF_MULTITHREADING
 void loopif_poll(struct netif *netif);
 #endif
 
 err_t loopif_init(struct netif *netif);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __NETIF_LOOPIF_H__ */

src/include/netif/slipif.h

@@ -36,7 +36,15 @@
 
 #include "lwip/netif.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 err_t slipif_init(struct netif * netif);
+
+#ifdef __cplusplus
+}
+#endif
  
 #endif