Question

I see a lot of PHP email implementations using “\r\n”, but I have also seen some of them using the PHP_EOL constant. Which one is better?

Thanks for any help
Metropolis

Answer 1

If this is to terminate lines in an email then it’s the spec for email that you need to look at, not what is used on any particular platform.

Lines in email are terminated by CRLF (“\r\n”) according to RFC2821

SMTP commands and, unless altered by a
service extension, message data,
are transmitted in “lines”. Lines
consist of zero or more data
characters terminated by the sequence
ASCII character “CR” (hex value 0D)
followed immediately by ASCII
character “LF” (hex value 0A). This
termination sequence is denoted as
in this document. Conforming
implementations MUST NOT recognize or
generate any other character or
character sequence as a line
terminator

That seems pretty clear that in an email the end of line is to be sent as \r\n . Sending anything else might work but it’s wrong unless you are using a “service extension” and if you are then you probably know what you should be sending anyway.