Description:
------------
I have file conf.xml:

<conf>
    <frequency></frequency>
</conf>

If I use $conf = simplxml_load_file(conf.xml) in object and than put the value of frequency into object variable ($this->frequency = $conf->frequency) everything is OK, but if I want to use this value in sleep($this->frequency) function, an error is displayed: 

Warning: sleep() expects parameter 1 to be long, object given in...

If I try to get variable type of frequency, "object" is returned...when I settype($this->frequency, "integer"), everything works good...

List of compiled modules:
apache2, bzip2, cgi, cli, crypt, exif, force-cgi-redirect, ftp, gd, iconv, imap, mhash, mysql, ncurses, nls, pcntl, pcre, posix, readline, reflection, session, simplexml, spell, spl, ssl, truetype, xml, xpm, xsl, zip, zlib

Expected result:
----------------
Clasic sleep(30); with no error

Actual result:
--------------
Warning: sleep() expects parameter 1 to be long, object given in...