Tcl_GetAssocData(interp, key, delProcPtr)
Tcl_SetAssocData(interp, key, delProc, clientData)
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
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 occupied by the clients 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 specifies the address of a
procedure to invoke if the interpreter is deleted before the association
is deleted. DeleteProc should have arguments and result that match
the type Tcl_InterpDeleteProc:
When deleteProc is invoked the clientData and interp
arguments will be the same as the corresponding arguments passed to
The deletion procedure will not be invoked if the association
is deleted before the interpreter is deleted.
typedef void Tcl_InterpDeleteProc(
Tcl_GetAssocData returns the datum stored in the association 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
Tcl_DeleteAssocData deletes an association with a specified key in
the given interpreter. Then it calls the deletion procedure.