Possible issue in mail() function?

Hi, I noticed that the mail() function in php 5.3.3 on gentoo linux triggers a warning when used. A simple debug script with the contents: <?php // recipient, subject, body mail("some@example.com", "mail() test", "This is a test"); ?> does send mail, but it also raises a warning: Warning: mail(1): failed to open stream: Permission denied in /var/www/www.example.com/htdocs/test-mail/index.php on line 5 After some googling [1] and fiddling with permissions, the message disappears when php has write permissions to the file /var/www/www.example.com/htdocs/test-mail/1 , in which it writes the following data: ==8<== mail() on [/var/www/www.example.com/htdocs/test-mail/index.php:5]: To: some@example.com -- Headers: ==8<== Is this some debug output that someone forgot to remove? When relevant, the sendmail_path used is "/usr/sbin/sendmail -t -i", which is a regular Postfix sendmail. [1] http://stackoverflow.com/questions/1906403 -- Kind regards, Tom Hendrikx