formhook(3X)                                                    formhook(3X)



NAME
       formhook - set hooks for automatic invocation by applications

SYNOPSIS
       ##include <>
       int setfieldinit(FORM *form, void (*func)(FORM *));
       void (*)(FORM *) fieldinit(const FORM *form);
       int setfieldterm(FORM *form, void (*func)(FORM *));
       void (*)(FORM *) fieldterm(const FORM *form);
       int setforminit(FORM *form, void (*func)(FORM *));
       void (*)(FORM *) forminit(const FORM *form);
       int setformterm(FORM *form, void (*func)(FORM *));
       void (*)(FORM *) formterm(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
       formdriver.

       The  function setfieldinit sets a hook to be called at form-post time
       and  each  time  the  selected  field  changes  (after   the   change).
       fieldinit  returns  the current field init hook, if any (NUL if there
       is no such hook).

       The function setfieldterm sets a hook to  be  called  at  form-unpost
       time  and  each  time  the  selected field changes (before the change).
       fieldterm returns the current field term hook, if any (NUL  if  there
       is no such hook).

       The  function  setforminit sets a hook to be called at form-post time
       and just after a page change once it is posted.  forminit returns  the
       current form init hook, if any (NUL if there is no such hook).

       The function setformterm sets a hook to be called at form-unpost time
       and just before a page change once it is posted.  forminit returns the
       current form term hook, if any (NUL if there is no such hook).

RETURN VALUE
       Routines  that  return  pointers  return NUL on error.  Other routines
       return one of the following:

       EOK The routine succeeded.

       ESYSTEMEROR
            System error occurred (see errno).

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

NOTES
       The  header  file  <>  automatically  includes  the  header  file
       <>.

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

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



                                                                 formhook(3X)