TclUpVar(3) Tcl Library Procedures TclUpVar(3)

NAME
       TclUpVar, TclUpVar2 - link one variable to another

SYNOPSIS
       ##iinncclluuddee <>

       int
       TTccllUUppVVaarr((interp, frameName, sourceName, destName, flags))

       int
       TTccllUUppVVaarr22((interp, frameName, name1, name2, destName, flags))

AARRGGUUMMEENNTTSS
       TclInterp         *interp          (in)      Interpreter    containing
                                                     variables;  also used for
                                                     error reporting.

       CONST char         *frameName       (in)      Identifies    the   stack
                                                     frame  containing  source
                                                     variable.   May  have any
                                                     of the forms accepted  by
                                                     the  uuppvvaarr  command, such
                                                     as ##00 or 11.

       CONST char         *sourceName      (in)      Name of source  variable,
                                                     in  the  frame  given  by
                                                     frameName.  May refer  to
                                                     a  scalar  variable or to
                                                     an array variable with  a
                                                     parenthesized index.

       CONST char         *destName        (in)      Name of destination vari-
                                                     able,  which  is  to   be
                                                     linked to source variable
                                                     so  that  references   to
                                                     destName   refer  to  the
                                                     other variable.  Must not
                                                     currently exist except as
                                                     an upvar-ed variable.

       int                flags            (in)      Either TCLGLOBALONLY or
                                                     0;    if  non-zero,  then
                                                     destName  is   a   global
                                                     variable;   otherwise  it
                                                     is a local to the current
                                                     procedure  (or  global if
                                                     no procedure is  active).

       CONST char         *name1           (in)      First   part   of  source
                                                     variable's  name  (scalar
                                                     name,  or  name  of array
                                                     without array index).

       CONST char         *name2           (in)      If source variable is  an
                                                     element   of   an  array,
                                                     gives the  index  of  the
                                                     element.     For   scalar
                                                     source   variables,    is
                                                     NULL.



DESCRIPTION
       TTccllUUppVVaarr  and  TTccllUUppVVaarr22  provide the same functionality as the uuppvvaarr
       command:  they make a link from a  source  variable  to  a  destination
       variable,  so  that  references to the destination are passed transpar-
       ently through to the source.  The name of the source  variable  may  be
       specified  either  as  a single string such as xxyyxx or aa((2244)) (by calling
       TTccllUUppVVaarr) or in two parts where the array name has been separated from
       the  element  name  (by  calling TTccllUUppVVaarr22).  The destination variable
       name is specified in a single string;  it may not be an array  element.

       Both  procedures  return  either TCLOK or TCLERROR, and they leave an
       error message in the interpreter's result if an error occurs.

       As with the uuppvvaarr command, the source variable need not  exist;  if  it
       does exist, unsetting it later does not destroy the link.  The destina-
       tion variable may exist at the time of the call,  but  if  so  it  must
       exist as a linked variable.


KKEEYYWWOORRDDSS
       linked variable, upvar, variable



Tcl                                   7.4                         TclUpVar(3)