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