Email. class. php: how to send BCC emails

Email. class. php mail class, how to send BCC Mail email. class. php must be a friend of PHP. now, if I send a large number of recipients, I want to send emails by BCC, I don't know how to set the source code of the class:/* MainFunction */functionsendmail ($ to, $ from, email. class. php mail class, how to send BCC
The e-mail. class. php class must be familiar to PHP friends. now, if I send a group of emails, many recipients will appear,
Now I want to send emails by BCC. I don't know how to set it.
This is the source code of the class:
/* Main Function */
Function sendmail ($ to, $ from, $ subject = "", $ body = "", $ mailtype, $ cc = "", $ bcc = "", $ additional_headers = "")
When I call:
$ Smtp-> sendmail ($ smtpemailto, $ smtpusermail, $ mailsubject, $ mailbody, $ mailtype );
The problem arises. I don't know why $ bcc should be set. its default value is "". I don't know whether it should be set to "bcc" or "true ".

I also asked Du Niang, but none of the others used this class. the appearance of online quiet waited for Niu Er.


------ Solution --------------------
$ Smtp-> sendmail ($ to, $ from, $ subject = "title", $ body = "content", $ mailtype, $ cc = "person who wants to cc ", $ bcc = "the person who wants bcc", $ additional_headers = "I don't know ")