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.
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