form_hook(3X) | form_hook(3X) |
NAME
form_hook - set hooks for automatic invocation by applicationsSYNOPSIS
#include <form.h>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).