DESIGN (xvforms) functions


LIBRARY ROUTINE

xvf_add_extra_call - add function call to GUI item

LIBRARY CALL

int xvf_add_extra_call(
   kform_struct *kformstruct,
   void        (*routine)(kaddr),
   kaddr        client_data,
   int          call_location)

INPUT

OUTPUT

none

RETURN VALUE

TRUE on success, FALSE on failure

DESCRIPTION

Some items on the Khoros GUI perform a particular function automatically, without ever returning flow control to the application program; they cannot be made "live" in order to force a return of flow control to the application. These items include:

(1) subform buttons, which map a subform (2) guide buttons, which map a pane (3) quit buttons, which close the subform or exit the program (4) help buttons, which put up a help page (5) answer input files, which update the GUI according to a GUI answer file (6) answer output files, which write out a GUI answer file

With these items, a mechanism is sometimes desired which will allow the programmer to call a particular routine when these items are used. For example, the programmer may want a certain routine to be called before a subform is mapped, after a pane is mapped, before the GUI is destroyed, or before a help page is displayed. For situations like this, xvf_add_extra_call() may be used to specify an additional routine that will be called by the built-in callback for the GUI item in question. xvf_add_extra_call() may be called more than once, if calls to more than one extra routine are needed.

ADDITIONAL INFORMATION

none

EXAMPLES

none

SIDE EFFECTS

none

RESTRICTIONS

This routine is only supported for kformstructs that are associated with subform buttons, guide buttons, quit buttons, help buttons, answer input file selections, or answer output file selections. Other GUI items either return control to the application program by their definition (as with Action buttons) or can be made "live" (as with Toggles, Input Files, Integer selections, etc); either case makes an additional callback installation redundant.

MODIFICATION

none

FILES

$DESIGN/objects/library/xvforms/src/extra.c

SEE ALSO

xvforms(3)

COPYRIGHT

Copyright (C) 1993 - 1997, Khoral Research, Inc. ("KRI") All rights reserved.