Tag Archives: C level API

hb_setListenerRemove()

Posted on by vivaclipper

hb_setListenerRemove()

Syntax

      C Prototype

      #include "hbset.h"
      hb_setListenerRemove( int handle ) --> int

Arguments

<handle> : The handle for the SET listener callback function to be removed.

Returns

The handle if the callback function could not be located or the negative value of the handle if the callback function was removed.

Description

This function removes a SET listener callback function.

Examples

      int handle = hb_setListenerAdd( callback_function );
      ...
      hb_setListenerRemove( handle );

Compliance

NA

Files

Library is core

Platforms

All

Seealso

hb_setListenerAdd()

hb_setListenerNotify()

Posted on by vivaclipper

hb_setListenerNotify()

Syntax

      C Prototype

      #include "hbset.h"
      hb_setListenerNotify( HB_set_enum set,  HB_set_listener_enum
      when ) --> int

Arguments

<set> : The number of the SET parameter that is to be or was changed.

<when> : Set to HB_SET_LISTENER_BEFORE when called before the SET parameter is to be changed and set to HB_SET_LISTENER_AFTER when called after the SET parameter has been changed.

Returns

<int>

Description

This function notifies all SET listener callback functions. It must be called any time you change the value of a SET parameter directly instead of using the Harbour SET function. Both before and after the change.

Examples

      hb_setListenerNotify( HB_SET_DECIMALS,  HB_SET_LISTENER_BEFORE );
      hb_set.HB_SET_DECIMALS = 3;
      hb_setListenerNotify( HB_SET_DECIMALS,  HB_SET_LISTENER_AFTER );

Compliance

NA

Files

Library is core

Platforms

All

Seealso

hb_setListenerAdd()

hb_setListenerAdd()

Posted on by vivaclipper

hb_setListenerAdd()

Syntax

      C Prototype

      #include "hbset.h"
      hb_setListenerAdd( PHB_SET_LISTENER_CALLBACK callback ) --> int

Arguments

<callback> : A pointer to a function taking two enum parameters and returning no value. The first parameter identifies the SET parameter that is to be changed and the second parameter identifies whether the call is from before or after the value is changed. The callback function will be called twice whenever a SET parameter is changed using the Harbour SET function. The first call takes place before the SET value is changed and the second one is after the SET parameter has been changed.

Returns

An integer value representing the callback handle, in case the caller needs to deactivate the callback function.

Description

This function allows a subsystem that needs to track the status of some SET parameters to be notified whenever a SET parameter gets changed.

Examples

      void callback_function( HB_set_enum set,  HB_set_listener_enum when )
      {
         printf("\nCalled for SET parameter %d %s changing.", 
            set,  (when ? "after" : "before"));
      }
      int handle = hb_setListenerAdd( callback_function );

Compliance

NA

Files

Library is core

Platforms

All

Seealso

hb_setListenerRemove()