- 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
- ARGUMENTS
- DESCRIPTION
- TCL_GLOBAL_ONLY
- TCL_NAMESPACE_ONLY
- TCL_LEAVE_ERR_MSG
- TCL_APPEND_VALUE
- TCL_LIST_ELEMENT
- SEE ALSO
- KEYWORDS
Tcl_SetVar2Ex, Tcl_SetVar, Tcl_SetVar2, Tcl_ObjSetVar2, Tcl_GetVar2Ex, Tcl_GetVar, Tcl_GetVar2, Tcl_ObjGetVar2, Tcl_UnsetVar, Tcl_UnsetVar2 - manipulate Tcl variables
#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)
- 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.
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
doesn't 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 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 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 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 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 isn't 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
doesn't 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 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.
Tcl_GetObjResult, Tcl_GetStringResult, Tcl_TraceVar
array, get variable, interpreter, object, scalar, set, unset, variable
Copyright © 1989-1993 The Regents of the University of California.
Copyright © 1994-1997 Sun Microsystems, Inc.
Copyright © 1995-1997 Roger E. Critchlow Jr.