form_hook - set hooks for automatic invocation by applications
SYNOPSIS
#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);
DESCRIPTION
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.
The function set_field_init sets a hook to be called at form-post time
and each time the selected field changes (after the change). field_init
returns the current field init hook, if any (NULL if there is no such
hook).
The function set_field_term sets a hook to be called at form-unpost time
and each time the selected field changes (before the change). field_term
returns the current field term hook, if any (NULL if there is no such
hook).
The function set_form_init sets a hook to be called at form-post time and
just after a page change once it is posted. form_init returns the
current form init hook, if any (NULL if there is no such hook).
The function set_form_term sets a hook to be called at form-unpost time
and just before a page change once it is posted. form_init
returns the current form term hook, if any (NULL if there is no such
hook).
RETURN VALUE
Routines that return pointers return NULL on error. Other routines
return one of the following:
