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/ipv6/lwip/icmp.h

@@ -39,6 +39,10 @@
 
 #include "lwip/netif.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define ICMP6_DUR  1
 #define ICMP6_TE   3
 #define ICMP6_ECHO 128    /* echo */
@@ -86,5 +90,9 @@ struct icmp_te_hdr {
   u32_t unused;
 };
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __LWIP_ICMP_H__ */
     

src/include/ipv6/lwip/inet.h

@@ -38,6 +38,10 @@
 #include "lwip/pbuf.h"
 #include "lwip/ip_addr.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 u16_t inet_chksum(void *data, u16_t len);
 u16_t inet_chksum_pbuf(struct pbuf *p);
 u16_t inet_chksum_pseudo(struct pbuf *p,
@@ -58,5 +62,9 @@ u32_t ntohl(u32_t n);
 #endif /* _NETINET_IN_H */
 #endif /* _MACHINE_ENDIAN_H_ */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __LWIP_INET_H__ */
 

src/include/ipv6/lwip/ip.h

@@ -39,6 +39,10 @@
 
 #include "lwip/err.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define IP_HLEN 40
 
 #define IP_PROTO_ICMP 58
@@ -104,6 +108,10 @@ err_t ip_output_if(struct pbuf *p, struct ip_addr *src, struct ip_addr *dest,
 void ip_debug_print(struct pbuf *p);
 #endif /* IP_DEBUG */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __LWIP_IP_H__ */
 
 

src/include/ipv6/lwip/ip_addr.h

@@ -34,6 +34,10 @@
 
 #include "lwip/arch.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define IP_ADDR_ANY 0
 
 #ifdef PACK_STRUCT_USE_INCLUDES
@@ -86,4 +90,8 @@ u8_t ip_addr_isany(struct ip_addr *addr);
          (ntohl(ipaddr->addr[3]) >> 16) & 0xffff, \
          ntohl(ipaddr->addr[3]) & 0xffff));
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __LWIP_IP_ADDR_H__ */