[Gambas-user] A Way to determine if Terminal supports color

[Tobias Boege]

On Fri, 30 Jul 2021, Brian G wrote:
> Maybe Tobias can help? 
> 
> Is there a way to use the color.available in gb.ncurses without having the screen automatically initialized. 
> 

gb.ncurses always calls initscr() as soon as the component is loaded to
establish a clean environment for the other classes "once and for all".
So there is no way to do that with gb.ncurses. It was conceived as a
user interface component (although not a lot came of it), not to inspect
low-level terminal capabilities. (I'm not saying that this wouldn't be
useful to have, maybe in gb.term?)

> Like using setupterm() and then call has_color() 
> To get the color available info from the terminal cap, so it never initializes the actual screen? 
> 
> Or is there another way to get this info? 
> 

Honestly, the quickest way is probably via Extern:

  Extern setupterm(term As String, fd As Integer, err As Pointer) As Integer In "libncursesw"
  Extern has_colors() As Integer In "libncursesw"

But note that when I try, inspired by your snippet,

  #include <stdio.h>
  #include <stdlib.h>
  #include <ncurses.h>
  #include <term.h>

  int main(void) {
    int err = 0;
    printf("%d ", setupterm(NULL, 1, &err));
    printf("%d ", err);
    printf("%d\n", has_colors());
    exit(0);
  }

I get the output "0 1 0", meaning my terminal is detected as hardcopy,
not capable of curses or color.

But when I properly initialize ncurses using initscr(),

  #include <stdio.h>
  #include <stdlib.h>
  #include <ncurses.h>

  int main(void) {
    initscr();
    int c = has_colors();
    endwin();

    printf("%d\n", c);
    exit(0);
  }

I get the expected output "1". Are you sure your method is supposed to work?

Best,
Tobias

-- 
"There's an old saying: Don't change anything... ever!" -- Mr. Monk