osx man page for form_hook

form_hook(3X)															     form_hook(3X)

NAME
       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:

       E_OK The routine succeeded.

       E_SYSTEM_ERROR
	    System error occurred (see errno).

SEE ALSO
       curses(3X), form(3X).

NOTES
       The header file <form.h> automatically includes the header file <curses.h>.

PORTABILITY
       These routines emulate the System V forms library.  They were not supported on Version 7 or BSD versions.

AUTHORS
       Juergen Pfeifer.  Manual pages and adaptation for new curses by Eric S. Raymond.

																     form_hook(3X)