HELP CALLER                              Steve Hardy, January 1982

    caller(<integer>)

This procedure may be used by procedures which need to know which
procedures have called them. It takes an integer as argument and returns
a procedure as result. CALLER(0) returns the caller of CALLER. CALLER(1)
returns the caller of the caller of CALLER, and so on. The procedure at
the top of the calling chain will always be *SETPOP.

CALLER_VALOF is like *VALOF except that it can be used to access or alter
the value of a variable local to a procedure higher up the calling chain
than the currently active procedure. see REF *IDENT/caller_valof
and HELP *VALOF for more details.

See also HELP
  *SYSCALLERS      - Procedure identifying callers of its own caller
  *CALLSTACKLENGTH - Returns the calling stack length of a procedure
  *CHAIN           - Exits from a procedure and calls another
  *CHAINFROM       - Similar to CHAINTO, but chains out of previous
                     activation
  *CHAINTO         - Runs a procedure within a previous procedure
                     activation
  *EXITTO          - Exits to a specified procedure activation
  *EXITFROM        - Exits from a specified procedure activation
  *PRMISHAP        - Prints error messages; user-redefinable

--- C.all/help/caller --------------------------------------------------
--- Copyright University of Sussex 1987. All rights reserved. ----------
