RTCS_selectset() cannot return you this information, as it has just one return value, which is socket handle. Latest RTCS already has BSD-like select() function and it can distinguish between data requests/ close or reset requests/ acknowledge received for send data. It is part of the Freescale MQX for Kinetis SDK, and also will be in next MQX classic.
In "older MQX" you need to use other RTCS functions. recv()/send() functions give you an error when remote endpoint is reset/connection closed, example:
retval = recv(sock,...);
if(retval < 0)
{
uint32_t error_code = RTCS_geterror(sock);
/* this might be for example RTCSERR_TCP_CONN_RLSD or RTCSERR_TCP_CONN_RESET */
....
RTCS_shutdown(sock, 0); /* complete graceful connection close. destroy socket. */
sock = RTCS_SOCKET_ERROR;
}
Personally I would use RTCS_selectset() only on listening sockets to block wait for connection requests. If you like non-portable customization, you can just read the state from the TCB of a valid TCP socket:
struct tcb_struct *tcb = ((struct socket_struct *)sock)->TCB_PTR;
if(NULL == tcb)
{
/* connection is released -> reset, abort */
}
else
{
uint16_t tcp_state = tcb->state;
/* it will be one of states defined in tcp_prv.h:
* TCB states */
#define LISTEN 0
#define SYN_SENT 1
#define SYN_RECEIVED 2
#define ESTABLISHED 3
#define FINWAIT_1 4
#define FINWAIT_2 5
#define CLOSE_WAIT 6
#define CLOSING 7
#define LAST_ACK 8
#define TIME_WAIT 9
#define CLOSED 10
#define BOUND 11
*/
}
Martin
