when using php 4.0.1 compiled with --enable-trans-sid:

this script:
<?
print "<a href='test.php'>";
?>

prints this:
<a href='test.php'&PHPSESSID=23hj2hj3j3jhhk2k>
and session id is not propagated.

php4 isn't acknowledging single quotes to be valid delimiters of href attribute values.

Note from W3C HTML 4.01 specification:
"By default, SGML requires that all attribute values be delimited using either double quotation marks (ASCII decimal 34) or single quotation marks (ASCII decimal 39). Single quote marks can be included within the attribute value when the value is delimited by double quote marks, and vice versa."