SLutf8_enable(-1);
SLtt_get_terminfo();
SLtt_get_screen_size();

err = SLsmg_init_smg();
if (err < 0)
	goto out;
err = SLang_init_tty(-1, 0, 0);
if (err < 0)
	goto out;

err = SLkp_init();
if (err < 0) {
	pr_err("TUI initialization failed.\n");
	goto out;
}

SLkp_define_keysym((char *)"^(kB)", SL_KEY_UNTAB);

signal(SIGSEGV, ui__signal_backtrace);
signal(SIGFPE, ui__signal_backtrace);
signal(SIGINT, ui__signal);
signal(SIGQUIT, ui__signal);
signal(SIGTERM, ui__signal);

perf_error__register(&perf_tui_eops);

ui_helpline__init();
ui_browser__init();
tui_progress__init();

hist_browser__init_hpp(); out:
return err; }

看这个 SLtt_get_terminfo 函数好像是干这个事情的，查看一下文档说明：       
http://www.jedsoft.org/slang/doc/html/cslang-8.html
```text
Of course not all terminals are color terminals. If the S-Lang global variable SLtt_Use_Ansi_Colors is non-zero, the terminal is assumed to be a color terminal. The SLtt_get_terminfo will try to determine whether or not the terminal supports colors and set this variable accordingly. It does this by looking for the capability in the terminfo/termcap database. Unfortunately many Unix databases lack this information and so the SLtt_get_terminfo routine will check whether or not the environment variable COLORTERM exists. If it exists, the terminal will be assumed to support ANSI colors and SLtt_Use_Ansi_Colors will be set to one. Nevertheless, the application should provide some other mechanism to set this variable, e.g., via a command line parameter.

When the SLtt_Use_Ansi_Colors variable is zero, all objects with numbers greater than one will be displayed in inverse video