For each socket to be tested, the SELECT macro can check for an
exception condition. The exception conditions are:
- The calling program (concurrent server) has issued a GIVESOCKET
command and the target subtask has successfully issued the TAKESOCKET
call. When this condition is selected, the calling program (concurrent
server) should issue CLOSE to dissociate itself from the socket.
- A socket has received out-of-band data. For this condition, a
READ macro returns the out-of-band data before the program data.
To determine if a socket has an exception condition, use the
ESNDMSK character string and set the appropriate bits to 1.