use_legacy_coding - override curses locale encoding checks

       Thomas Dickey

use_legacy_coding,  an  ncurses extension to the curses library, permits customiztion of unctrl(3NCURSES)
       behavior, suppressing isprint(3)-based checks within the library that would  normally  cause  nonprinting
       characters  to  be  rendered  in visible form.  The alteration affects only byte-wide characters with the
       most significant bit set.

       The level parameter controls the result.

              0    The  library  functions  normally,  rendering  nonprinting   characters   as   described   in
                   unctrl(3NCURSES),

              1    the library ignores isprint for codes in the range 160-255.

              2    the  library  ignores isprint for codes in the range 128-255.  It also modifies the output of
                   unctrl(3NCURSES), showing codes in the range 128-159 as is.

use_legacy_coding is an ncurses extension.

ncurses 5.6 (2006) introduced use_legacy_coding to support lynx(1)'s font-switching feature.

use_legacy_coding - override curses locale encoding checks

       Applications  employing  ncurses  extensions  should  condition  their  use  on  the  visibility  of  the
       NCURSES_VERSION preprocessor macro.

       If the curses screen has not been initialized, or the level parameter is out of range,  use_legacy_coding
       returns ERR.  Otherwise, it returns the previous level.

unctrl(3NCURSES)

ncurses 6.5                                        2024-09-14                            legacy_coding(3NCURSES)

#include<curses.h>intuse_legacy_coding(intlevel);