diff --git a/CHANGELOG b/CHANGELOG
index 9e95004a..43604d0c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -19,6 +19,11 @@ HISTORY
 
   ++ New features:
 
+  2008-01-12 Frédéric Bernon
+  * tcpip.h, tcpip.c, api.h, api_lib.c, api_msg.c, sockets.c: replace the field
+    netconn::sem per netconn::op_completed like suggested for the task #7490
+    "Add return value to sys_mbox_post".
+
   2008-01-12 Frédéric Bernon
   * api_msg.c, opt.h: replace DEFAULT_RECVMBOX_SIZE per DEFAULT_TCP_RECVMBOX_SIZE,
     DEFAULT_UDP_RECVMBOX_SIZE and DEFAULT_RAW_RECVMBOX_SIZE (to optimize queues
diff --git a/src/api/api_lib.c b/src/api/api_lib.c
index 896b6b35..22b65a31 100644
--- a/src/api/api_lib.c
+++ b/src/api/api_lib.c
@@ -79,10 +79,10 @@ netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto, netconn_cal
 
     if (conn->err != ERR_OK) {
       LWIP_ASSERT("freeing conn without freeing pcb", conn->pcb.tcp == NULL);
-      LWIP_ASSERT("conn has no sem", conn->sem != SYS_SEM_NULL);
+      LWIP_ASSERT("conn has no op_completed", conn->op_completed != SYS_SEM_NULL);
       LWIP_ASSERT("conn has no recvmbox", conn->recvmbox != SYS_MBOX_NULL);
       LWIP_ASSERT("conn->acceptmbox shouldn't exist", conn->acceptmbox == SYS_MBOX_NULL);
-      sys_sem_free(conn->sem);
+      sys_sem_free(conn->op_completed);
       sys_mbox_free(conn->recvmbox);
       memp_free(MEMP_NETCONN, conn);
       return NULL;
diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index 508153aa..ccb4c0dd 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -282,9 +282,9 @@ err_tcp(void *arg, err_t err)
     API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
     sys_mbox_post(conn->recvmbox, NULL);
   }
-  if (conn->sem != SYS_SEM_NULL && conn->state == NETCONN_CONNECT) {
+  if (conn->op_completed != SYS_SEM_NULL && conn->state == NETCONN_CONNECT) {
     conn->state = NETCONN_NONE;
-    sys_sem_signal(conn->sem);
+    sys_sem_signal(conn->op_completed);
   }
   if (conn->acceptmbox != SYS_MBOX_NULL) {
     /* Register event with callback */
@@ -296,7 +296,7 @@ err_tcp(void *arg, err_t err)
        since the pcb has already been deleted! */
     conn->state = NETCONN_NONE;
     /* wake up the waiting task */
-    sys_sem_signal(conn->sem);
+    sys_sem_signal(conn->op_completed);
   }
 }
 
@@ -497,12 +497,12 @@ netconn_alloc(enum netconn_type t, netconn_callback callback)
   }
 #endif
 
-  if ((conn->sem = sys_sem_new(0)) == SYS_SEM_NULL) {
+  if ((conn->op_completed = sys_sem_new(0)) == SYS_SEM_NULL) {
     memp_free(MEMP_NETCONN, conn);
     return NULL;
   }
   if ((conn->recvmbox = sys_mbox_new(size)) == SYS_MBOX_NULL) {
-    sys_sem_free(conn->sem);
+    sys_sem_free(conn->op_completed);
     memp_free(MEMP_NETCONN, conn);
     return NULL;
   }
@@ -558,8 +558,8 @@ netconn_free(struct netconn *conn)
     conn->acceptmbox = SYS_MBOX_NULL;
   }
 
-  sys_sem_free(conn->sem);
-  conn->sem = SYS_SEM_NULL;
+  sys_sem_free(conn->op_completed);
+  conn->op_completed = SYS_SEM_NULL;
 
   memp_free(MEMP_NETCONN, conn);
 }
@@ -607,7 +607,7 @@ do_close_internal(struct netconn *conn)
     API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
     API_EVENT(conn, NETCONN_EVT_SENDPLUS, 0);
     /* wake up the application task */
-    sys_sem_signal(conn->sem);
+    sys_sem_signal(conn->op_completed);
   }
   /* If closing didn't succeed, we get called again either
      from poll_tcp or from sent_tcp */
@@ -655,8 +655,8 @@ do_delconn(struct api_msg_msg *msg)
   API_EVENT(msg->conn, NETCONN_EVT_RCVPLUS, 0);
   API_EVENT(msg->conn, NETCONN_EVT_SENDPLUS, 0);
 
-  if (msg->conn->sem != SYS_SEM_NULL) {
-    sys_sem_signal(msg->conn->sem);
+  if (msg->conn->op_completed != SYS_SEM_NULL) {
+    sys_sem_signal(msg->conn->op_completed);
   }
 }
 
@@ -724,7 +724,7 @@ do_connected(void *arg, struct tcp_pcb *pcb, err_t err)
     setup_tcp(conn);
   }
   conn->state = NETCONN_NONE;
-  sys_sem_signal(conn->sem);
+  sys_sem_signal(conn->op_completed);
   return ERR_OK;
 }
 #endif /* LWIP_TCP */
@@ -740,7 +740,7 @@ void
 do_connect(struct api_msg_msg *msg)
 {
   if (msg->conn->pcb.tcp == NULL) {
-    sys_sem_signal(msg->conn->sem);
+    sys_sem_signal(msg->conn->op_completed);
     return;
   }
 
@@ -748,13 +748,13 @@ do_connect(struct api_msg_msg *msg)
 #if LWIP_RAW
   case NETCONN_RAW:
     msg->conn->err = raw_connect(msg->conn->pcb.raw, msg->msg.bc.ipaddr);
-    sys_sem_signal(msg->conn->sem);
+    sys_sem_signal(msg->conn->op_completed);
     break;
 #endif /* LWIP_RAW */
 #if LWIP_UDP
   case NETCONN_UDP:
     msg->conn->err = udp_connect(msg->conn->pcb.udp, msg->msg.bc.ipaddr, msg->msg.bc.port);
-    sys_sem_signal(msg->conn->sem);
+    sys_sem_signal(msg->conn->op_completed);
     break;
 #endif /* LWIP_UDP */
 #if LWIP_TCP
@@ -983,7 +983,7 @@ do_writemore(struct netconn *conn)
     if (conn->write_delayed != 0)
 #endif
     {
-      sys_sem_signal(conn->sem);
+      sys_sem_signal(conn->op_completed);
     }
   }
 #if LWIP_TCPIP_CORE_LOCKING
@@ -1015,7 +1015,7 @@ do_write(struct api_msg_msg *msg)
       if (do_writemore(msg->conn) != ERR_OK) {
         LWIP_ASSERT("state!", msg->conn->state == NETCONN_WRITE);
         UNLOCK_TCPIP_CORE();
-        sys_arch_sem_wait(msg->conn->sem, 0);
+        sys_arch_sem_wait(msg->conn->op_completed, 0);
         LOCK_TCPIP_CORE();
         LWIP_ASSERT("state!", msg->conn->state == NETCONN_NONE);
       }
diff --git a/src/api/sockets.c b/src/api/sockets.c
index dd871c80..bc7dbef5 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -48,6 +48,7 @@
 #include "lwip/igmp.h"
 #include "lwip/inet.h"
 #include "lwip/tcp.h"
+#include "lwip/raw.h"
 #include "lwip/udp.h"
 #include "lwip/tcpip.h"
 
@@ -1301,7 +1302,7 @@ lwip_getsockopt(int s, int level, int optname, void *optval, socklen_t *optlen)
   data.optlen = optlen;
   data.err = err;
   tcpip_callback(lwip_getsockopt_internal, &data);
-  sys_arch_sem_wait(sock->conn->sem, 0);
+  sys_arch_sem_wait(sock->conn->op_completed, 0);
   /* maybe lwip_getsockopt_internal has changed err */
   err = data.err;
 
@@ -1485,7 +1486,7 @@ lwip_getsockopt_internal(void *arg)
     break;
 #endif /* LWIP_UDP */
   } /* switch (level) */
-  sys_sem_signal(sock->conn->sem);
+  sys_sem_signal(sock->conn->op_completed);
 }
 
 int
@@ -1675,7 +1676,7 @@ lwip_setsockopt(int s, int level, int optname, const void *optval, socklen_t opt
   data.optlen = &optlen;
   data.err = err;
   tcpip_callback(lwip_setsockopt_internal, &data);
-  sys_arch_sem_wait(sock->conn->sem, 0);
+  sys_arch_sem_wait(sock->conn->op_completed, 0);
   /* maybe lwip_setsockopt_internal has changed err */
   err = data.err;
 
@@ -1859,7 +1860,7 @@ lwip_setsockopt_internal(void *arg)
     break;
 #endif /* LWIP_UDP */
   }  /* switch (level) */
-  sys_sem_signal(sock->conn->sem);
+  sys_sem_signal(sock->conn->op_completed);
 }
 
 int
diff --git a/src/api/tcpip.c b/src/api/tcpip.c
index c7a3ca1f..97ae41db 100644
--- a/src/api/tcpip.c
+++ b/src/api/tcpip.c
@@ -418,7 +418,7 @@ tcpip_apimsg(struct api_msg *apimsg)
     msg.type = TCPIP_MSG_API;
     msg.msg.apimsg = apimsg;
     sys_mbox_post(mbox, &msg);
-    sys_arch_sem_wait(apimsg->msg.conn->sem, 0);
+    sys_arch_sem_wait(apimsg->msg.conn->op_completed, 0);
     return ERR_OK;
   }
   return ERR_VAL;
diff --git a/src/include/lwip/api.h b/src/include/lwip/api.h
index 216dc447..31d767f2 100644
--- a/src/include/lwip/api.h
+++ b/src/include/lwip/api.h
@@ -119,7 +119,7 @@ struct netconn {
   /** the last error this netconn had */
   err_t err;
   /** sem that is used to synchroneously execute functions in the core context */
-  sys_sem_t sem;
+  sys_sem_t op_completed;
   /** mbox where received packets are stored until they are fetched
       by the netconn application thread (can grow quite big) */
   sys_mbox_t recvmbox;
diff --git a/src/include/lwip/tcpip.h b/src/include/lwip/tcpip.h
index fb2dbdeb..541d28ac 100644
--- a/src/include/lwip/tcpip.h
+++ b/src/include/lwip/tcpip.h
@@ -59,7 +59,7 @@ extern sys_sem_t lock_tcpip_core;
 #define LOCK_TCPIP_CORE()
 #define UNLOCK_TCPIP_CORE()
 #define TCPIP_APIMSG(m)       tcpip_apimsg(m)
-#define TCPIP_APIMSG_ACK(m)   sys_sem_signal(m->conn->sem)
+#define TCPIP_APIMSG_ACK(m)   sys_sem_signal(m->conn->op_completed)
 #define TCPIP_NETIFAPI(m)     tcpip_netifapi(m)
 #define TCPIP_NETIFAPI_ACK(m) sys_sem_signal(m->sem)
 #endif /* LWIP_TCPIP_CORE_LOCKING */