LwIP\src\include\lwip\中第1913行如下：
/** LWIP_NETCONN_FULLDUPLEX==1: Enable code that allows reading from one thread,
- writing from a 2nd thread and closing from a 3rd thread at the same time.
- ATTENTION: This is currently really alpha! Some requirements:
-
- LWIP_NETCONN_SEM_PER_THREAD==1 is required to use one socket/netconn from
- multiple threads at once *
-
- sys_mbox_free() has to unblock receive tasks waiting on recvmbox/acceptmbox
- and prevent a task pending on this during/after deletion
*/
#if !defined LWIP_NETCONN_FULLDUPLEX || defined DOXYGEN
#define LWIP_NETCONN_FULLDUPLEX 1
#endif
)
