INT 31H 0d03H: Free Serialization on Shared Memory

                                                    Compatibility: DPMI 1.0+ 
 Expects: AX    0d02H
          SI:DI handle of shared memory block as obtained via INT 31H 0d00H
          DX    option flags: bit 0: 0=release exclusive serialization
                                     1=release shared serialization
                              bit 1: 0=don't free pending serialization
                                     1=free pending serialization (see note)
                               2-15: reserved, must be 0
 Returns: CF    NC (clear) if successful; else AX = DPMI Error Code
    Info: This releases a access of a shared memory block that was obtained
          by a previous call to INT 31H 0d02H (serialize on shared memory).

   Notes: ■ The host maintains four serialization counts for each VM
            (exclusive, shared, pending shared, and pending exclusive).
            This fn actually only decrements the relevant count -- the
            serialization is actually freed only when the count goes to 0.

          ■ A suspended client continues to receive interrupts and can use
            this call in an interrupt handler to cancel a serialization
            that has blocked a foreground client.  In that case, the call
            made by the foreground client is returned an error code of
            8005H (request canceled).

See Also: DPMI API
          INT 2fH: Multiplex Interrupt
          DOS Functions