What effect does 'crlf' (new line character) actually have in e-mail preferences?

[eluser]Andy Ingham[/eluser]
Hi All,

I've found it mentioned in lots of places that 'crlf' should generally be set to "\r\n", but my question is what effect does this atually have?

For example, if I have the following line...

Code:

$this->email->message("first line"."\n"."second line");

...then I'm coding it explicitly. Is there some kind of constant that the 'crlf' setting is affecting?

Andy