Tcl_SetAssocData(3) Tcl Library Procedures 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.

const char *key (in) Key for association
with which to store
data or from which to
delete or retrieve
data. Typically the
module prefix 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 association.
Ignored if NULL.

ClientData clientData (in) Arbitrary one-word
value associated with
the given key in this
interpreter. 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 occupied 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 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:

typedef void Tcl_InterpDeleteProc(
ClientData clientData,
Tcl_Interp *interp);

When deleteProc is invoked the clientData and interp arguments 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 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
returns NULL.

Tcl_DeleteAssocData deletes an association with a specified key in
the given interpreter. Then it calls the deletion procedure.

KEYWORDS

association, data, deletion procedure, interpreter, key

Tcl 7.5 Tcl_SetAssocData(3)