Unlocks pages that were previously locked in memory by the Lock
    Pages in Memory ($LCKPAG) service. Locked pages are automatically
    unlocked and deleted at image exit.

    Format

      SYS$ULKPAG  inadr ,[retadr] ,[acmode]

    C Prototype

      int sys$ulkpag  (struct _va_range *inadr, struct _va_range

                      *retadr, unsigned int acmode);

1  –  Arguments

 inadr

    OpenVMS usage:address_range
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Starting and ending virtual addresses of the pages to be
    unlocked. The inadr argument is the address of a 2-longword array
    containing, in order, the starting and ending process virtual
    addresses.

    Only the virtual page number portion of each virtual address is
    used; the low-order byte-within-page bits are ignored. If the
    starting and ending virtual addresses are the same, a single page
    is unlocked.

    If more than one page is being unlocked and you need to determine
    specifically which pages had been previously unlocked, you should
    unlock the pages one at a time, that is, one page per call
    to $ULKPAG. The condition value returned by $ULKPAG indicates
    whether the page was previously unlocked.

 retadr

    OpenVMS usage:address_range
    type:         longword (unsigned)
    access:       write only
    mechanism:    by reference-array reference or descriptor
    Starting and ending process virtual addresses of the pages
    actually unlocked by $ULKPAG. The retadr argument is the address
    of a 2-longword array containing, in order, the starting and
    ending process virtual addresses.

    If an error occurs while multiple pages are being unlocked,
    retadr specifies those pages that were successfully unlocked
    before the error occurred. If no pages were successfully
    unlocked, both longwords in the retadr array contain the value
    -1.

 acmode

    OpenVMS usage:access_mode
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Access mode on behalf of which the request is being made. The
    acmode argument is a longword containing the access mode. The
    $PSLDEF macro defines the symbols for the four access modes.

    The most privileged access mode used is the access mode of the
    caller. To unlock any specified page, the resultant access mode
    must be equal to or more privileged than the access mode of the
    owner of that page.