S
PL_
PL_
PL_WRITE.AVAIL{%}{WTHEN\ELSE}
*
      S$ = CALLFN('00':         \
                  FNR.WRITE.AVAIL:             \ ;* Function code
                  OCONV({%1},'MCDX')'R%4'    \ ;* P.NO
                  )
*
      IF S$[3,4] = IPX.SOCKET.NO THEN
         RES = OCONV(S$[7,4],'MCXD')
         IF RES > 32768 THEN
            RES = RES - 65536
         END
         ERR = 0
      END ELSE
         ERR = 1
         RES = 0
      END
*
      IF NOT(ERR) AND RES >= 0 {%2}
