Input Parameters | Significance |
DtvLong idm | button area Id |
BUT_FNC_LAY_LNR fnc | pointer to button-listener function |
Output Parameters | Significance |
none | - |
Return Code | Significance |
0 | all OK |
1 | old button-listener function was overwritten |
-1 | no button area Id passed |
With the help of the button-listener callback function you can react on changes to the local button area structure. The button-listener function is automatically invoked by all functions that change button areas, such as dal_but_cre_sel.
The button-listener function must correspond to the specification void fnc(idb, typ, fnc_nam, par). The parameters are:
If the same listener function is used for all objects (menus, button areas, masks), the enumeration type DTV_LAY_LNR_TYP can be used to determine from which object the listener function was called.