Question

how to implement a function that will return the OS name? detect the environment where the program running on?

win2000/xp/vista/win7 etc…?

Answer 1

Something like this:

function osver: string;
begin
  result := 'Unknown (Windows ' + IntToStr(Win32MajorVersion) + '.' + IntToStr(Win32MinorVersion) + ')';
  case Win32MajorVersion of
    4:
      case Win32MinorVersion of
        0: result := 'Windows 95';
        10: result := 'Windows 98';
        90: result := 'Windows ME';
      end;
    5:
      case Win32MinorVersion of
        0: result := 'Windows 2000';
        1: result := 'Windows XP';
      end;
    6:
      case Win32MinorVersion of
        0: result := 'Windows Vista';
        1: result := 'Windows 7';
        2: result := 'Windows 8';
        3: result := 'Windows 8.1';
      end;
    10:
      case Win32MinorVersion of
        0: result := 'Windows 10';
      end;
  end;
end;

There is really no need to call GetVersionEx because SysUtils.pas has InitPlatformID in its initialization clause. Hence the global constants Win32MajorVersion and Win32MinorVersion (and friends) will be populated already.