, string $pass
The username must start with an alphabetical character and must NOT contain any other characters than alphanumerics, the underline and dash.
Returns TRUE on success, PEAR_Error on failure.
|FILE_PASSWD_E_EXISTS_ALREADY||the user to add already exists|
|FILE_PASSWD_E_INVALID_CHARS||the username to add contains illegal characters|
This function can not be called statically.