int dal_mas_set_lay_fnc (idm, fnc)

Sets a mask-listener callback function.

Input Parameters Significance
DtvLong idm mask Id
MAS_FNC_LAY_LNR fnc pointer to the mask-listener function

Output Parameters Significance
none -

Return Code Significance
0 all OK
1 old mask-listener function was overwritten
-1 no mask Id passed

With the help of the mask-listener callback function you can react on changes to the local mask structure. The mask-listener function is automatically invoked by all functions that change masks, such as dal_mas_ins_fld.

The mask-listener function must correspond to the specification void fnc(idm, typ, fnc_nam). 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.