Improve documentation: Some words about multiple execution contexts in lwIP

src/api/api_lib.c

@@ -3,7 +3,7 @@
  * Sequential API External module
  * 
  * @defgroup netconn Netconn API
- * @ingroup threadsafe_api
+ * @ingroup sequential_api
  * Thread-safe, to be called from non-TCPIP threads only.
  * TX/RX handling based on @ref netbuf (containing @ref pbuf)
  * to avoid copying data around.

src/api/netifapi.c

@@ -3,7 +3,7 @@
  * Network Interface Sequential API module
  *
  * @defgroup netifapi NETIF API
- * @ingroup threadsafe_api
+ * @ingroup sequential_api
  * Thread-safe functions to be called from non-TCPIP threads
  * 
  * @defgroup netifapi_netif NETIF related

src/api/sockets.c

@@ -3,7 +3,7 @@
  * Sockets BSD-Like API module
  *
  * @defgroup socket Socket API
- * @ingroup threadsafe_api
+ * @ingroup sequential_api
  * BSD-style socket API.\n
  * Thread-safe, to be called from non-TCPIP threads only.\n
  * Can be activated by defining @ref LWIP_SOCKET to 1.\n

src/include/lwip/tcpip.h

@@ -52,7 +52,9 @@ extern "C" {
 #if LWIP_TCPIP_CORE_LOCKING
 /** The global semaphore to lock the stack. */
 extern sys_mutex_t lock_tcpip_core;
+/** Lock lwIP core mutex (needs @ref LWIP_TCPIP_CORE_LOCKING 1) */
 #define LOCK_TCPIP_CORE()     sys_mutex_lock(&lock_tcpip_core)
+/** Unlock lwIP core mutex (needs @ref LWIP_TCPIP_CORE_LOCKING 1) */
 #define UNLOCK_TCPIP_CORE()   sys_mutex_unlock(&lock_tcpip_core)
 #else /* LWIP_TCPIP_CORE_LOCKING */
 #define LOCK_TCPIP_CORE()