form_hook(3x)                    Library calls                   form_hook(3x)
       form_hook - set hooks for automatic invocation by applications
       #include <form.h>
       int set_field_init(FORM *form, Form_Hook func);
       Form_Hook field_init(const FORM *form);
       int set_field_term(FORM *form, Form_Hook func);
       Form_Hook field_term(const FORM *form);
       int set_form_init(FORM *form, Form_Hook func);
       Form_Hook form_init(const FORM *form);
       int set_form_term(FORM *form, Form_Hook func);
       Form_Hook form_term(const FORM *form);
       These  functions make it possible to set hook functions to be called at
       various points in the automatic processing  of  input  event  codes  by
       form_driver.
       sets  a  hook to be called at form-post time and each time the selected
       field changes (after the change).
       returns the current field init hook, if any (NULL if there is  no  such
       hook).
       sets a hook to be called at form-unpost time and each time the selected
       field changes (before the change).
       returns the current field term hook, if any (NULL if there is  no  such
       hook).
       sets a hook to be called at form-post time and just after a page change
       once it is posted.
       returns the current form init hook, if any (NULL if there  is  no  such
       hook).
       sets  a  hook  to  be called at form-unpost time and just before a page
       change once it is posted.
       returns the current form term hook, if any (NULL if there  is  no  such
       hook).
       Routines  that  return  pointers  return NULL on error.  Other routines
       return one of the following:
       E_OK The routine succeeded.
       E_SYSTEM_ERROR
            System error occurred (see errno(3)).
       These routines emulate the System  V  forms  library.   They  were  not
       supported on Version 7 or BSD versions.
       Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S.
       Raymond.
       curses(3x), form(3x)
ncurses 6.5                       2024-12-28                     form_hook(3x)