[|PUP (MACRO)[%
 
 
 >>--PUP--+---------+------------------------------><
          '-ctlfile-'
 
 
[|Purpose[%
 
 Use the PUP ("Pipe UPdates") macro to apply multi-level updates,
 one at a time, to the current file in the XEDIT ring.
 
[|Operands[%
 
 ctlfile
     is the filename of the UPDATE control file to be used to
     determine the updates to be applied.  If no control file is
     specified, a default control file is found by:
 
    1.  Searching the XEDIT ring for a file with filetype CNTRL.
    2.  Searching the accessed disks for the first file named
        CONTROL DEFAULT.  If such a file is found, the first
        record is assumed to contain the filename of a control
        file.
    3.  Using a hard-coded default (defined near the top of the
        XEDIT macro).
 
[|Usage Notes[%
 
 1. When PUP is first invoked, it determines the control file to use and
    builds a list of the updates to be applied.  If any updates have been
    applied already (if, for example, you entered XEDIT with the CTL and
    UNTIL options), then those updates are deleted from the list.
 
    Each time it is invoked, PUP attempts to apply the next update.  It
    always brings the update log into the XEDIT ring, whether or not the
    update applies successfully.
 
    If the update applies successfully, PUP also takes the following
    steps:
 
    1.  Makes the updated file the new master file.
    2.  FILEs the update, if it had been altered.
    3.  Brings the next update file into the ring.
    4.  Issues a warning if the next update contains delete statements.
 
    If the update does not apply, the master file remains unchanged and
    the update log becomes the current file in the ring.  After changing
    the update file (no need to FILE it first), you can invoke PUP again.
 
    After PUP has been invoked once, there is no need to specify the
    control file.  PUP remembers the list of updates to be applied.  If
    you want the list of the remaining updates to be refreshed (e.g., if
    you have added an update to an auxfile), then specify the control
    file name the next time you invoke PUP.
 
    PUP always uses a file that is in the current XEDIT ring (control
    file, auxfile, or update file) in preference to one that is on a
    disk.