dll files undetected

Hey,

I was wondering, what makes the dll files "undetected"? And what does that exactly mean? I know it bypasses the gameguard to inject the file into the game but after that is it still 'undetectable'?
While you are in game and you've injected the dll files, can the GS/GM see that you are using a hack?

Thanks in advance,

.dlls are hacks made by coders that hack the game to whatever the coder said it will do and hex editing will make the hack undetected so you dont get 3rd party error and gm cant see your hacking unless you make it obvious when your playing and with euro farm if you farm too much they are obviously going to catch you i suggest farming 30-60k euros max