form_userptr - associate application data with a form item
int set_form_userptr(FORM *form, void *userptr);
void* form_userptr(const FORM *form);
Every form and every form item has a field that can be used to hold
application-specific data (that is, the form-driver code leaves it
alone). These functions get and set the form user pointer field.
The function form_userptr returns NULL on error. The function
set_form_userptr returns one of the following:
E_OK The routine succeeded.
System error occurred (see errno).
The header file <form.h> automatically includes the header file
These routines emulate the System V forms library. They were not sup-
ported on Version 7 or BSD versions.
The user pointer should be a void pointer. We leave it as a char
pointer for SVr4 compatibility.
Juergen Pfeifer. Manual pages and adaptation for new curses by Eric S.