tcl_setassocdata(3)

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.

CONST
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.

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. Then it calls the
deletion procedure.

KEYWORDS

association, data, deletion procedure, interpreter, key

Tcl 7.5 Tcl_SetAssocData(3)