Int 7A  - Novell Netware - Ipxodi V2.12+ - Open Look-ahead Socket          [N]

   BX = 0023h
   DX = socket number (0000h for dynamic allocation)
   ES:SI -> Look Ahead handler (see #3502)
   BP = desired lookahead size (0000h-0080h)

Return: AL = status
       00h successful
       DX = assigned socket number (big-endian)
       FEh maximum number of sockets already open
       FFh specific socket already opened by another application
   DS,FLAGS preserved
   all other registers may be destroyed

Notes: the socket will always be long-lived, and must thus be explicitly
     closed with INT 7A/BX=0001h before the Look Ahead handler code is
     removed from memory (i.e. the program terminates)
   this function is only supported if INT 2F/AX=7A00h returns ES:BX
     pointing at an IPX version greater than 3.30
   the desired lookahead size is the smallest-size packet (including IPX
     header) that should be passed to the lookahead handler when it
     arrives

See Also: INT 7A/BX=0000h,INT 7A/BX=0001h

(Table 3502)
Call IPX Look-Ahead handler with:
   AX = packet's destination socket
   DS:SI -> look-ahead structure (see #2694 at INT 2F/AX=C000h"LSL")
   DF clear
   interrupt disabled (must remain disabled)

Return: AX = packet use
       0000h application want packet
       ES:SI -> ODI ECB (see #2695 at INT 2F/AX=C000h"LSL")
       8001h application does not want packet
   ZF set if AX=0000h
   DS,DI,BP,SS,SP preserved
   interrupts disabled