Provided by: tcl8.5-doc_8.5.15-2ubuntu1_all bug

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)

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

       const 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)

       const char *
       Tcl_GetVar(interp, varName, flags)

       const 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 containing variable.

       const 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 complete  name  including  both
                                             variable  name  and index.  May include :: namespace
                                             qualifiers to specify a  variable  in  a  particular
                                             namespace.

       const 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  additional
                                             information. See below for valid values.

       const char *varName (in)              Name  of  variable.   May   include   ::   namespace
                                             qualifiers  to  specify  a  variable in a particular
                                             namespace.  May refer to a  scalar  variable  or  an
                                             element of an array.

       const char *newValue (in)             New   value  for  variable,  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.  The name may include a series of :: namespace
                                             qualifiers  to  specify  a  variable in a particular
                                             namespace.  May refer to a  scalar  variable  or  an
                                             element of an array variable.

       Tcl_Obj *part2Ptr (in)                If non-NULL, points to an object containing 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 different than the newValuePtr or newValue argument, due
       to modifications 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 arguments
       to the procedures described above.  Under normal circumstances,  the  return  value  is  a
       pointer  to  the  variable's  value.   For  Tcl_GetVar2Ex  and Tcl_ObjGetVar2 the value is
       returned as a pointer to a Tcl_Obj.  For Tcl_GetVar 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  does  not
       exist  or  an array element is specified for a scalar variable), then NULL is returned and
       an error message is left in interp's result if the TCL_LEAVE_ERR_MSG flag bit is set.

       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 procedures above.  If the variable is successfully
       removed  then  TCL_OK  is returned.  If the variable cannot be removed because it does not
       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 procedures 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 varName does not 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 specified 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
              generated 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 varName 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 combination 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  variable  is looked up first in the current
              namespace, then in the global namespace.  However, 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 procedure 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 is not set then no error message is left
              and the interpreter's result will not be modified.

       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  sublist  (i.e.  the  variable's  current value is empty, or contains the single
              character “{”, or ends in “  }”).   When  appending,  the  original  value  of  the
              variable must also be a valid list, so that the operation is the appending of a new
              list element onto a list.

       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 variable (e.g. the variable does not exist or an  array  element  is
       specified for a scalar variable), then NULL is returned.

       Tcl_UnsetVar  and  Tcl_UnsetVar2 may be used to remove a variable, so that future calls to
       Tcl_GetVar or Tcl_GetVar2 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  does  not  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