The task is to check that the terminal supports Unicode output, before outputting a Unicode character. If the terminal supports Unicode, then the terminal should output a Unicode delta (U+25b3). If the terminal does not support Unicode, then an appropriate error should be raised.

Note that it is permissible to use system configuration data to determine terminal capabilities if the system provides such a facility.

$ include "seed7_05.s7i";
  include "environment.s7i";
  include "console.s7i";
 
const proc: main is func
  begin
    if pos(lower(getenv("LANG")), "utf") <> 0 or
       pos(lower(getenv("LC_ALL")), "utf") <> 0 or
       pos(lower(getenv("LC_CTYPE")), "utf") <> 0 then
      writeln(STD_CONSOLE, "Unicode is supported on this terminal and U+25B3 is: △");
    else
      writeln("Unicode is not supported on this terminal.");
    end if;
  end func;