diff --git a/components/net/at/at_socket/at_socket.h b/components/net/at/at_socket/at_socket.h
index 8e90609082b146ad7c2996159394142f8de4835c..7d9ce91f39dee16140f019aed8c48f92852f4303 100644
--- a/components/net/at/at_socket/at_socket.h
+++ b/components/net/at/at_socket/at_socket.h
@@ -32,6 +32,10 @@
 #include <netdb.h>
 #include <sys/socket.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef AT_SOCKET_RECV_BFSZ
 #define AT_SOCKET_RECV_BFSZ            512
 #endif
@@ -160,4 +164,8 @@ void at_scoket_device_register(const struct at_device_ops *ops);
 
 #endif /* RT_USING_SAL */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* AT_SOCKET_H__ */
diff --git a/components/net/at/include/at.h b/components/net/at/include/at.h
index d0040f86cfd09dd34ffc212c47b804df7aa04f37..1ef0388a65f67e955671c49e84b62143e17ac5c4 100644
--- a/components/net/at/include/at.h
+++ b/components/net/at/include/at.h
@@ -27,6 +27,9 @@
 
 #include <rtthread.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 #define AT_SW_VERSION                  "0.3.0"
 
 #define DBG_ENABLE
@@ -251,4 +254,8 @@ void at_port_reset(void);
 void at_port_factory_reset(void);
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __AT_H__ */
diff --git a/components/net/sal_socket/impl/af_inet.h b/components/net/sal_socket/impl/af_inet.h
index 10a77d58710bd433e6539e751020449eac5579e0..8d6be25eaaf6b3d699764b4847e3fb0075e3981f 100644
--- a/components/net/sal_socket/impl/af_inet.h
+++ b/components/net/sal_socket/impl/af_inet.h
@@ -27,6 +27,10 @@
 
 #include <rtthread.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifdef SAL_USING_LWIP
 /* lwIP protocol family register */
 int lwip_inet_init(void);
@@ -37,4 +41,8 @@ int lwip_inet_init(void);
 int at_inet_init(void);
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __AF_INET_H__ */
diff --git a/components/net/sal_socket/include/dfs_net/dfs_net.h b/components/net/sal_socket/include/dfs_net/dfs_net.h
index 2a21fe3858b19300e40fdb6d9a44d01a74a74289..242d3c5334f765146fa30cc977d57cc5b6829aa5 100644
--- a/components/net/sal_socket/include/dfs_net/dfs_net.h
+++ b/components/net/sal_socket/include/dfs_net/dfs_net.h
@@ -26,12 +26,12 @@
 #ifndef DFS_NET_H__
 #define DFS_NET_H__
 
+#include <dfs_file.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#include <dfs_file.h>
-
 const struct dfs_file_ops* dfs_net_get_fops(void);
 int dfs_net_getsocket(int fd);
 
diff --git a/components/net/sal_socket/include/sal.h b/components/net/sal_socket/include/sal.h
index e1a6dbedba576b47f8be94bd9b793a502cd78de4..62ffaa303efb66888d2d3ff0533dc02ea2c3b74f 100644
--- a/components/net/sal_socket/include/sal.h
+++ b/components/net/sal_socket/include/sal.h
@@ -28,6 +28,10 @@
 #include <dfs_file.h>
 #include <rtdevice.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if !defined(socklen_t) && !defined(SOCKLEN_T_DEFINED)
 typedef uint32_t socklen_t;
 #endif
@@ -103,4 +107,8 @@ int sal_proto_family_register(const struct proto_family *pf);
 int sal_proto_family_unregister(const struct proto_family *pf);
 struct proto_family *sal_proto_family_find(const char *name);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_H__ */
diff --git a/components/net/sal_socket/include/sal_ipaddr.h b/components/net/sal_socket/include/sal_ipaddr.h
index 814d1d16e99f29cbdc52f30f8e1250ede13ff0ea..c40fc18374d287cf1990694dd79de54d8e1efe6e 100644
--- a/components/net/sal_socket/include/sal_ipaddr.h
+++ b/components/net/sal_socket/include/sal_ipaddr.h
@@ -26,6 +26,10 @@
 
 #include "sal_type.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** IPv4 only: set the IP address given as an u32_t */
 #define ip4_addr_set_u32(dest_ipaddr, src_u32) ((dest_ipaddr)->addr = (src_u32))
 /** IPv4 only: get the IP address as an u32_t */
diff --git a/components/net/sal_socket/include/sal_netdb.h b/components/net/sal_socket/include/sal_netdb.h
index 12f7abe6b79a441e6b9bde550f01c1c143d11a4d..0a31f26fae227c34e954e75453d54e3854bf63c4 100644
--- a/components/net/sal_socket/include/sal_netdb.h
+++ b/components/net/sal_socket/include/sal_netdb.h
@@ -26,6 +26,10 @@
 
 #include <sal_socket.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define EAI_NONAME      200
 #define EAI_SERVICE     201
 #define EAI_FAIL        202
@@ -88,4 +92,8 @@ int sal_getaddrinfo(const char *nodename,
        const struct addrinfo *hints,
        struct addrinfo **res);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_NETDB_H__ */
diff --git a/components/net/sal_socket/include/sal_socket.h b/components/net/sal_socket/include/sal_socket.h
index 872fd5ca95d8e4039a11c6113f5ad539e8cfe19d..477112392c9a99995f1f5cb760a089879e57fcc4 100644
--- a/components/net/sal_socket/include/sal_socket.h
+++ b/components/net/sal_socket/include/sal_socket.h
@@ -27,6 +27,10 @@
 
 #include "sal_ipaddr.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if !defined(socklen_t) && !defined(SOCKLEN_T_DEFINED)
 typedef uint32_t socklen_t;
 #endif
@@ -175,4 +179,8 @@ int sal_socket(int domain, int type, int protocol);
 int sal_closesocket(int socket);
 int sal_ioctlsocket(int socket, long cmd, void *arg);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_SOCKET_H__ */
diff --git a/components/net/sal_socket/include/sal_type.h b/components/net/sal_socket/include/sal_type.h
index 0446d5f4e18b2b5932c387e58fdd8edb60ea6a8a..907b3d02b4ec966d11781e5c82eb308feb1eb70f 100644
--- a/components/net/sal_socket/include/sal_type.h
+++ b/components/net/sal_socket/include/sal_type.h
@@ -28,6 +28,10 @@
 #include <stdlib.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef int8_t    err_t;
 typedef uint8_t   u8_t;
 typedef int8_t    s8_t;
@@ -37,4 +41,8 @@ typedef uint32_t  u32_t;
 typedef int32_t   s32_t;
 typedef uintptr_t mem_ptr_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_TYPE_H__ */
diff --git a/components/net/sal_socket/src/sal_socket.c b/components/net/sal_socket/src/sal_socket.c
index 920ce720c213af9025c272c63397a914ac1dc3b9..7b6683a69cd56408d7f2b9761c94572cde5a5b0a 100644
--- a/components/net/sal_socket/src/sal_socket.c
+++ b/components/net/sal_socket/src/sal_socket.c
@@ -738,7 +738,6 @@ struct hostent *sal_gethostbyname(const char *name)
             {
                 return hst;
             }
-            continue;
         }
     }
 
@@ -759,7 +758,6 @@ int sal_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
             {
                 return res;
             }
-            continue;
         }
     }
 
@@ -796,7 +794,6 @@ int sal_getaddrinfo(const char *nodename,
             {
                 return ret;
             }
-            continue;
         }
     }