Include <? ?> in string literal

[Paul E Collins]

I want to programmaticall y remove any <?...?section occurring on a
single line. However, my regular expression needs to contain ?and
that causes the interpreter to choke with a parse error. What's the
standard way to include ?in a string?

My current (failing) attempt is:

$line = preg_replace('/<\?.*?\?>/', '', $line);

Eq.