Callback Signature List

List of all callback defined by libmkkernel

The callback have to be a C proc or method …

Callback signature

#define MkObjectDeleteCallF_ARGS             \
  MK_RT_ARGS                                 \
  MK_OBJN const obj __parser__(internal),    \
  MK_STRN const typeName,                    \
  MK_HDL  const typeHdl,                     \
  MK_HDL  const objHdl,                      \
  MK_CBP  const __data__                     \
 
#define MkObjectDeleteCallF_CALL  MK_RT_CALL obj, __data__
 
__parser__(flags=public-internal)
typedef enum MkErrorE ( MK_DECL *MkObjectDeleteCallF) ( MkObjectDeleteCallF_ARGS ) ;
 
#define MkObjectDeleteFreeF_ARGS  MK_RT_ARGS MK_CBP *dataP __parser__(inout)
 
__parser__(flags=public-internal)
typedef void ( MK_DECL *MkObjectDeleteFreeF) ( MkObjectDeleteFreeF_ARGS ) ;
 
__parser__(class=MkObjectC,callback-name=ObjectDelete,callback-null)
MK_EXTERN enum MkErrorE MK_DECL MkObjectDeleteCallbackSetup_RT (
  MK_PARSER_RT
  MK_STRN               ident ,
  MkObjectDeleteCallF   fCall       __parser__(callback-call),
  MK_CBP                callback    __parser__(callback-data),
  MkObjectDeleteFreeF   fFree       __parser__(callback-free),
  MK_STRN               filter      __parser__(default=NULL)
) MK_ATTR_RT_STATIC ;

Note

For the C-language the fCall is the function called and the callback is the additional data. This is different for the non-C-languges from (C,C++,C#,VB.NET,Java,Python,Ruby,Perl,PHP,Tcl or GO).

For the non-C-language the fCall is internal and the callback is the target-language-callback as data attribute.

Read more about how to define a service-callback in theLink .

Callback example

RPC server

Example about the delete-callback-setup from the RPC server example/c/LibSq3LiteRpcServer.c

ServerSetup : The DeleteCallback is usually installed in the Setup-Callback but only once.

  if (MQ_IS_SERVER_PARENT(mqctx)) {
    // call “sDeleteCall” ONLY when deleting an instance whose class name matches the regular expression “^Sq3”
    MkObjectDeleteCallbackSetup_E("LibSq3LiteRpcServer", sDeleteCall, mqctx, NULL, "^Sq3");
  }

The DeleteCallback is called before the deletion. In the RPC example, the RPC client is informed about the impending deletion.

static enum MkErrorE sDeleteCall ( MkObjectDeleteCallF_ARGS )
{
  MQ_CTX mqctx = MqCtx(__data__);
  if (mqctx == NULL) return MK_OK;
  return  MqSend(mqctx,"E","%DEL:CHH", typeName, typeHdl, objHdl);
}

ServerCleanup : If the RPC server is deleted, the DeleteCallback is no longer needed and is therefore also deleted.

  if (MQ_IS_SERVER_PARENT(mqctx)) {
    MkObjectDeleteCallbackCleanup("LibSq3LiteRpcServer");
  }

RPC client

Example about the delete-callback-setup from the RPC client example/tcl/LibSq3LiteRpcClient.tcl

Constructor: Add the DeleteCallback-Service if not already available :

oo::define Sq3LiteRpc constructor { rpcHdl args} {
  next $rpcHdl {*}$args

  # only use "DeleteCallback" on the initial (Parent) context
  set parentRpc         [$rpcHdl LinkGetParent]

  # add service "%DEL" as static-callback "Sq3LiteDestructor"
  $parentRpc ServiceCreate "%DEL" [list Sq3LiteRpc Sq3LiteDestructor $rpcHdl]
}

DeleteCallback: If the objHdl is still available delete the obj :

oo::define Sq3LiteRpc self method Sq3LiteDestructor {parentRpc childRpc} {
  set typName [$parentRpc ReadSTR]
  set typHdl  [$parentRpc ReadHDL]
  set objHdl  [$parentRpc ReadHDL]

  # type=MyClassS -> rpc=MyClassRpc
  set classRpc  [string replace $typName end end Rpc]

  # hdl=objHdl -> obj
  set obj   [$childRpc CacheLookup $classRpc $objHdl]

  # is "obj" already deleted ?
  if {$obj eq "MK_NULL"} return

  # now delete "obj"
  try {
    # the "objHdl" is already deleted on server, avoid resent 
    $obj hdl 0
    $obj destroy
  } on error {} {
    [$parentRpc ErrorCatch] Println
  }
}
oo::define Sq3LiteRpc export Sq3LiteDestructor

Global MkObjectDeleteCallbackSetup_RT (MK_RT mkrt, MK_STRN ident, MkObjectDeleteCallF fCall, MK_CBP callback, MkObjectDeleteFreeF fFree, MK_STRN filter)

MkObjectDeleteCallbackSetup