mailex - a reimplemenation of the function mail using a smtp-server to send mails

The function mailex is a reimplementation of the built-in php function mail. The difference is that you can specify a smtp-server which is used to send the mails. The function has exactly the same parameters like the mail function. If the mail-header-lines "From: " and "To: " are not specified by the user they will be generated automatically.