In nonblocking mode, operations return immediately even if the data does not exist, or a connection is not established yet. It is the responsibility of the application to poll the operation until completion. When a server socket is configured as nonblocking, the accepted private socket inherits the nonblocking attribute. If there are several nonblocking sockets, TI recommends using sl_Select with time-out 0, instead of polling each socket separately.

The commands sl_Recv/ and sl_RecvFrom are unique, and allow nonblocking operation although the socket is in blocking mode. Two options are available for this mode.

• A single call to sl_Recv or sl_RecvFrom in nonblocking mode by using the SL_MSG_DONTWAIT flag. The API returns immediately with data if it exists or with the error SL_ERROR_BSD_EAGAIN. This action does not affect any socket settings or the following calls to sl_Recv/ and sl_RecvFrom.
• Setting a receive time-out. This setting applies for all subsequent calls to sl_Recv/ and sl_RecvFrom. When time-out expires, sl_Recv and sl_RecvFrom returns with SL_ERROR_BSD_EAGAIN, or earlier if the data arrives.

An example of setting the socket as non-blocking:

_i16 Status;
SlSockNonblocking_t BlockingOption;
BlockingOption.NonBlockingEnabled = 1;
// Enable or disable non-blocking mode
Status = sl_SetSockOpt(Sd,SL_SOL_SOCKET,SL_SO_NONBLOCKING,(_u8*)&BlockingOption,sizeof(BlockingOption));
if( Status )
{
    // error 
}

An example of a non-blocking TCP connect:

_i16 Status;
SlSockAddrIn_t  Addr;
Addr.sin_family      = SL_AF_INET;
Addr.sin_port        = sl_Htons(5001);
Addr.sin_addr.s_addr = sl_Htonl(SL_IPV4_VAL(192,168,1,31));
Status = SL_ERROR_BSD_EALREADY;
while( 0 > Status ) 
{
Status = sl_Connect(Sd, ( SlSockAddr_t *)&Addr, sizeof(SlSockAddr_t));
if( 0 > Status ) 
{
if( SL_ERROR_BSD_EALREADY != Status )
{
// errorbreak;
}
}
}

An example of receiving data with no wait flag:

_i16 Status;
_i8  RecvBuf[1460];
 Status = sl_Recv(Sd, RecvBuf, 1460, SL_MSG_DONTWAIT);
if( (0 > Status) && (SL_ERROR_BSD_EAGAIN != Status) )
{
// error
}

An example of setting the receive data timeout:

_i16 Status;
struct SlTimeval_t TimeVal;
TimeVal.tv_sec =  5;             // Seconds
TimeVal.tv_usec = 0;             // Microseconds. 10000 microseconds resolution
Status = sl_SetSockOpt(Sd,SL_SOL_SOCKET,SL_SO_RCVTIMEO, (_u8 *)&TimeVal, sizeof(TimeVal));    // Enable receive timeoutif( Status )
{
// error 
}