Re: Access to echo, cbreak state without accessing SCREEN internals

[Thomas Dickey]

On Wed, Aug 09, 2023 at 04:59:31PM -0400, Bill Gray wrote:
>    ncurses already has some extension functions to get at internals of
> (opaque) WINDOW structs.  Would you be willing to consider adding these two
> similar extension functions to get at internals of the SCREEN structure?
> 
> int is_cbreak( void);
> int is_echo( void);
> 
>    My use case is as follows : I've written "extended" wgetn_wstr() and
> wgetnstr() functions that are outside the Curses library,  but behave
> (mostly) the way the standard Curses library functions do,  with add-ons
> such as allowing one to insert/delete in the middle of the text,  use the
> mouse,  supply default text,  set the field width on-screen,  and so on.
> These functions can then be used with ncurses,  PDCurses,  or PDCursesMod.
> 
>    The ncurses (and PDCurses and PDCursesMod) library implementations of
> those functions save the existing cbreak and echo states,  call cbreak() and

actually it saves/restores nl, as well:

    save_flags = sp->_tty_flags;
    NCURSES_SP_NAME(nl) (NCURSES_SP_ARG);
    NCURSES_SP_NAME(noecho) (NCURSES_SP_ARG);
    if (!save_flags._raw)
        NCURSES_SP_NAME(cbreak) (NCURSES_SP_ARG);

I suppose that adding is_XXX functions won't hurt.

> noecho(),  and then restore the original states.  Since wgetnstr() and
> friends are internal Curses functions,  having them just access WINDOW and
> SCREEN structure elements directly is not a problem.
> 
>    But my functions are _not_ internal to Curses,  and shouldn't be
> accessing SCREEN elements.  And,  of course,  it can't if SCREEN is opaque,
> as can happen with ncurses and PDCursesMod.  So I need functions to tell me
> if we're in echo and/or cbreak mode.

SCREEN's "always" opaque :-)
 
>    I assume that in ncurses,  these extensions would also lead to
> 
> int is_cbreak_sp( const SCREEN *sp);
> int is_echo_sp( const SCREEN *sp);
> 
>    There may be other innards to which access would be helpful,  but these
> are the only two I've encountered thus far.
> 
>    FWIW,  the code where I need such functions is at
> 
> https://github.com/Bill-Gray/find_orb/blob/master/getstrex.cpp#L94
> 
>    I currently use PDC_getcbreak() and PDC_getecho(),  but these are
> PDCursesMod-only functions.
> 
> Thanks!           -- Bill
> 

-- 
Thomas E. Dickey <dickey@invisible-island.net>
https://invisible-island.net

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