Deassigns (releases) an I/O channel previously acquired using the
    Assign I/O Channel ($ASSIGN) service.

    Format

      SYS$DASSGN  chan

    C Prototype

      int sys$dassgn  (unsigned short int chan);

1  –  Argument

 chan

    OpenVMS usage:channel
    type:         word (unsigned)
    access:       read only
    mechanism:    by value
    Number of the I/O channel to be deassigned. The chan argument is
    a word containing this number.