NAME

       Tcl_SetVar2Ex,  Tcl_SetVar,  Tcl_SetVar2,  Tcl_ObjSetVar2,
       Tcl_GetVar2Ex,  Tcl_GetVar,  Tcl_GetVar2,  Tcl_ObjGetVar2,
       Tcl_UnsetVar, Tcl_UnsetVar2 - manipulate Tcl variables


SYNOPSIS

       #include <tcl.h>

       Tcl_Obj *                                                  |
       Tcl_SetVar2Ex(interp, name1, name2, newValuePtr, flags)    |

       char *
       Tcl_SetVar(interp, varName, newValue, flags)

       char *
       Tcl_SetVar2(interp, name1, name2, newValue, flags)

       Tcl_Obj *
       Tcl_ObjSetVar2(interp, part1Ptr, part2Ptr, newValuePtr, flags)

       Tcl_Obj *                                                  |
       Tcl_GetVar2Ex(interp, name1, name2, flags)                 |

       char *
       Tcl_GetVar(interp, varName, flags)

       char *
       Tcl_GetVar2(interp, name1, name2, flags)

       Tcl_Obj *
       Tcl_ObjGetVar2(interp, part1Ptr, part2Ptr, flags)

       int
       Tcl_UnsetVar(interp, varName, flags)

       int
       Tcl_UnsetVar2(interp, name1, name2, flags)


ARGUMENTS

       Tcl_Interp   *interp        (in)      Interpreter contain­
                                             ing variable.

       char         *name1         (in)      Contains the name of
                                             an   array  variable
                                             (if  name2  is  non-
                                             NULL)  or  (if name2
                                             is NULL) either  the
                                             name   of  a  scalar
                                             variable or  a  com­
                                             plete name including
                                             both  variable  name
                                             qualifiers  to spec­
                                             ify a variable in  a
                                             particular    names­
                                             pace.

       char         *name2         (in)      If  non-NULL,  gives
                                             name    of   element
                                             within   array;   in
                                             this case name1 must
                                             refer  to  an  array
                                             variable.

       Tcl_Obj      *newValuePtr   (in)      Points   to   a  Tcl |
                                             object    containing |
                                             the  new  value  for |
                                             the variable.

       int          flags          (in)      OR-ed combination of
                                             bits providing addi­
                                             tional  information.
                                             See  below for valid
                                             values.

       char         *varName       (in)      Name  of   variable.
                                             May    include    ::
                                             namespace qualifiers
                                             to  specify  a vari­
                                             able in a particular
                                             namespace.       May
                                             refer  to  a  scalar
                                             variable  or an ele­
                                             ment  of  an  array.
                                             If  the  name refer­
                                             ences an element  of
                                             an  array,  then the
                                             name  must   be   in
                                             writable     memory:
                                             Tcl will make tempo­
                                             rary   modifications
                                             to it while  looking
                                             up the name.

       char         *newValue      (in)      New  value for vari­
                                             able, specified as a
                                             NULL-terminated
                                             string.  A  copy  of
                                             this value is stored
                                             in the variable.

       Tcl_Obj      *part1Ptr      (in)      Points  to   a   Tcl
                                             object    containing
                                             the variable's name.
                                             namespace qualifiers
                                             to specify  a  vari­
                                             able in a particular
                                             namespace.       May
                                             refer  to  a  scalar
                                             variable or an  ele­
                                             ment   of  an  array
                                             variable.

       Tcl_Obj      *part2Ptr      (in)      If non-NULL,  points
                                             to  an  object  con­
                                             taining the name  of
                                             an element within an
                                             array  and  part1Ptr
                                             must   refer  to  an
                                             array variable.
_________________________________________________________________



DESCRIPTION

       These procedures are used to  create,  modify,  read,  and
       delete Tcl variables from C code.

       Tcl_SetVar2Ex, Tcl_SetVar, Tcl_SetVar2, and Tcl_ObjSetVar2 |
       will create a new variable  or  modify  an  existing  one. |
       These procedures set the given variable to the value given |
       by newValuePtr or newValue and return  a  pointer  to  the |
       variable's  new  value,  which is stored in Tcl's variable |
       structure.  Tcl_SetVar2Ex and Tcl_ObjSetVar2 take the  new |
       value  as  a  Tcl_Obj  and  return a pointer to a Tcl_Obj. |
       Tcl_SetVar and Tcl_SetVar2 take the new value as a  string |
       and  return a string; they are usually less efficient than |
       Tcl_ObjSetVar2.  Note that the return value may be differ­ |
       ent than the newValuePtr or newValue argument, due to mod­
       ifications made by write traces.  If an  error  occurs  in
       setting the variable (e.g. an array variable is referenced
       without giving an index into the array) NULL  is  returned
       and  an  error  message  is left in interp's result if the
       TCL_LEAVE_ERR_MSG flag bit is set.

       Tcl_GetVar2Ex, Tcl_GetVar, Tcl_GetVar2, and Tcl_ObjGetVar2 |
       return  the current value of a variable.  The arguments to |
       these procedures are treated in the same way as the  argu­ |
       ments  to  the  procedures  described above.  Under normal |
       circumstances, the return value is a pointer to the  vari­ |
       able's  value.   For  Tcl_GetVar2Ex and Tcl_ObjGetVar2 the |
       value is returned as a pointer to a Tcl_Obj.  For Tcl_Get­ |
       Var  and  Tcl_GetVar2  the  value is returned as a string; |
       this  is  usually  less  efficient,  so  Tcl_GetVar2Ex  or |
       Tcl_ObjGetVar2  are  preferred.   If an error occurs while
       reading the variable (e.g. the variable doesn't  exist  or
       an array element is specified for a scalar variable), then

       Tcl_UnsetVar  and  Tcl_UnsetVar2  may  be used to remove a
       variable, so that future attempts  to  read  the  variable
       will  return  an error.  The arguments to these procedures
       are treated in the same way as the arguments to the proce­
       dures above.  If the variable is successfully removed then
       TCL_OK is returned.  If the  variable  cannot  be  removed
       because it doesn't exist then TCL_ERROR is returned and an
       error  message  is  left  in  interp's   result   if   the
       TCL_LEAVE_ERR_MSG flag bit is set.  If an array element is
       specified, the given element  is  removed  but  the  array
       remains.   If an array name is specified without an index,
       then the entire array is removed.

       The name of a variable may be specified  to  these  proce­
       dures in four ways:

       [1]    If   Tcl_SetVar,  Tcl_GetVar,  or  Tcl_UnsetVar  is
              invoked, the variable name is  given  as  a  single
              string,  varName.   If  varName  contains  an  open
              parenthesis and ends with a close parenthesis, then
              the  value between the parentheses is treated as an
              index (which can have any  string  value)  and  the
              characters  before  the  first open parenthesis are
              treated as the name of an array variable.  If  var­
              Name  doesn't  have parentheses as described above,
              then the entire string is treated as the name of  a
              scalar variable.

       [2]    If  the  name1 and name2 arguments are provided and
              name2 is non-NULL, then an array element is  speci­
              fied and the array name and index have already been
              separated by the caller: name1  contains  the  name
              and  name2  contains the index.  An error is gener­ |
              ated if name1  contains  an  open  parenthesis  and |
              ends  with  a close parenthesis (array element) and |
              name2 is non-NULL.                                  |

       [3]                                                               ||
              If  name2  is NULL, name1 is treated just like var­ |
              Name in case [1] above (it can be either  a  scalar |
              or an array element variable name).

       The  flags  argument may be used to specify any of several
       options to the procedures.  It consists of an OR-ed combi­
       nation of the following bits.

       TCL_GLOBAL_ONLY
              Under  normal  circumstances the procedures look up
              variables as  follows.   If  a  procedure  call  is
              active  in interp, the variable is looked up at the
              current level of procedure  call.   Otherwise,  the
              if  this  bit  is set in flags then the variable is
              looked up only in  the  global  namespace  even  if
              there   is   a  procedure  call  active.   If  both
              TCL_GLOBAL_ONLY and TCL_NAMESPACE_ONLY  are  given,
              TCL_GLOBAL_ONLY is ignored.

       TCL_NAMESPACE_ONLY
              If  this  bit  is set in flags then the variable is
              looked up only in the current namespace; if a  pro­
              cedure is active its variables are ignored, and the
              global namespace is also ignored unless it  is  the
              current namespace.

       TCL_LEAVE_ERR_MSG
              If  an  error  is  returned  and this bit is set in
              flags, then an error message will be  left  in  the
              interpreter's  result,  where  it  can be retrieved
              with Tcl_GetObjResult or  Tcl_GetStringResult.   If
              this  flag  bit  isn't set then no error message is
              left and the interpreter's result will not be modi­
              fied.

       TCL_APPEND_VALUE
              If  this bit is set then newValuePtr or newValue is
              appended to the current value instead of  replacing
              it.   If  the variable is currently undefined, then
              the bit is ignored.  This bit is only used  by  the
              Tcl_Set* procedures.

       TCL_LIST_ELEMENT
              If this bit is set, then newValue is converted to a
              valid Tcl list element before setting (or appending
              to)  the  variable.   A separator space is appended
              before the new list element unless the list element
              is  going to be the first element in a list or sub­
              list (i.e. the variable's current value  is  empty,
              or  contains the single character ``{'', or ends in
              `` }'').

       Tcl_GetVar and Tcl_GetVar2 return the current value  of  a
       variable.   The  arguments to these procedures are treated
       in the  same  way  as  the  arguments  to  Tcl_SetVar  and
       Tcl_SetVar2.  Under normal circumstances, the return value
       is a pointer to the variable's value (which is  stored  in
       Tcl's  variable  structure  and will not change before the
       next call to Tcl_SetVar or Tcl_SetVar2).   Tcl_GetVar  and
       Tcl_GetVar2   use   the   flag  bits  TCL_GLOBAL_ONLY  and
       TCL_LEAVE_ERR_MSG, both of which have the same meaning  as
       for  Tcl_SetVar.   If an error occurs in reading the vari­
       able (e.g. the variable doesn't exist or an array  element
       is   specified  for  a  scalar  variable),  then  NULL  is
       returned.
       variable,  so  that future calls to Tcl_GetVar or Tcl_Get­
       Var2 for the variable will return an error.  The arguments
       to  these  procedures  are  treated in the same way as the
       arguments to Tcl_GetVar and Tcl_GetVar2.  If the  variable
       is  successfully  removed then TCL_OK is returned.  If the
       variable cannot be removed because it doesn't  exist  then
       TCL_ERROR  is returned.  If an array element is specified,
       the given element is removed but the array remains.  If an
       array  name is specified without an index, then the entire
       array is removed.



SEE ALSO

       Tcl_GetObjResult, Tcl_GetStringResult, Tcl_TraceVar



KEYWORDS

       array, get variable,  interpreter,  object,  scalar,  set,
       unset, variable