Index of Section 3 Manual Pages
| Interix / SUA | Tcl_SetVar2Ex.3 | Interix / SUA |
Tcl_SetVar(3) Tcl Library Procedures Tcl_SetVar(3)
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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_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 contain-
ing 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 com-
plete name including
both variable name
and index. May
include :: namespace
qualifiers to spec-
ify a variable in a
particular names-
pace.
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 addi-
tional information.
See below for valid
values.
CONST 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.
CONST 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.
The name may include
a series of ::
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.
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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
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 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 |
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 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
variable is looked up first in the current names-
pace, 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 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
`` }''). 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 ele-
ment 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_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
Tcl 8.1 Tcl_SetVar(3)