Tcl_SetAssocData(3)
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NAME
Tcl_GetAssocData, Tcl_SetAssocData, Tcl_DeleteAssocData -
manage associations of string keys and user specified data
with Tcl interpreters.
SYNOPSIS
#include <<tcl.h>>
ClientData
Tcl_GetAssocData(interp, key, delProcPtr)
Tcl_SetAssocData(interp, key, delProc, clientData)
Tcl_DeleteAssocData(interp, key)
ARGUMENTS
Tcl_Interp *interp (in) Interpreter
in which to
execute the
specified
command.
char *key (in) Key for
association
with which
to store
data or
from which
to delete
or retrieve
data. Typ-
ically the
module pre-
fix for a
package.
Tcl_InterpDeleteProc *delProc (in) Procedure
to call
when interp
is deleted.
Tcl_InterpDeleteProc **delProcPtr (in) Pointer to
location in
which to
store
address of
current
deletion
procedure
for associ-
ation.
Ignored if
NULL.
ClientData clientData (in) Arbitrary
one-word
value asso-
ciated with
the given
key in this
inter-
preter.
This data
is owned by
the caller.
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DESCRIPTION
These procedures allow extensions to associate their own
data with a Tcl interpreter. An association consists of a
string key, typically the name of the extension, and a
one-word value, which is typically a pointer to a data
structure holding data specific to the extension. Tcl
makes no interpretation of either the key or the value for
an association.
Storage management is facilitated by storing with each
association a procedure to call when the interpreter is
deleted. This procedure can dispose of the storage occu-
pied by the client's data in any way it sees fit.
Tcl_SetAssocData creates an association between a string
key and a user specified datum in the given interpreter.
If there is already an association with the given key,
Tcl_SetAssocData overwrites it with the new information.
It is up to callers to organize their use of names to
avoid conflicts, for example, by using package names as
the keys. If the deleteProc argument is non-NULL it spec-
ifies the address of a procedure to invoke if the inter-
preter is deleted before the association is deleted.
DeleteProc should have arguments and result that match the
type Tcl_InterpDeleteProc:
typedef void Tcl_InterpDeleteProc(
ClientData clientData,
Tcl_Interp *interp);
When deleteProc is invoked the clientData and interp argu-
ments will be the same as the corresponding arguments
passed to Tcl_SetAssocData. The deletion procedure will
not be invoked if the association is deleted before the
interpreter is deleted.
Tcl_GetAssocData returns the datum stored in the associa-
tion with the specified key in the given interpreter, and
if the delProcPtr field is non-NULL, the address indicated
by it gets the address of the delete procedure stored with
this association. If no association with the specified key
exists in the given interpreter Tcl_GetAssocData returns
NULL.
Tcl_DeleteAssocData deletes an association with a speci-
fied key in the given interpreter. It does not call the
deletion procedure.
KEYWORDS
association, data, deletion procedure, interpreter, key