<HTML ><HEAD ><TITLE >Spotting References</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="PHP Manual" HREF="index.html"><LINK REL="UP" TITLE="References Explained" HREF="language.references.html"><LINK REL="PREVIOUS" TITLE="Unsetting References" HREF="language.references.unset.html"><LINK REL="NEXT" TITLE="Features" HREF="features.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=ISO-8859-1"></HEAD ><BODY CLASS="sect1" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP Manual</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="language.references.unset.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" >Chapter 15. References Explained</TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="features.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="sect1" ><H1 CLASS="sect1" ><A NAME="language.references.spot" ></A >Spotting References</H1 ><P > Many syntax constructs in PHP are implemented via referencing mechanisms, so everything told above about reference binding also apply to these constructs. Some constructs, like passing and returning by-reference, are mentioned above. Other constructs that use references are: </P ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="references.global" ></A ><TT CLASS="literal" >global</TT > References</H2 ><P > When you declare variable as <B CLASS="command" >global $var</B > you are in fact creating reference to a global variable. That means, this is the same as: <DIV CLASS="informalexample" ><A NAME="AEN5701" ></A ><P ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><PRE CLASS="php" >$var =& $GLOBALS["var"];</PRE ></TD ></TR ></TABLE ><P ></P ></DIV > </P ><P > That means, for example, that unsetting <TT CLASS="varname" >$var</TT > won't unset global variable. </P ></DIV ><DIV CLASS="sect2" ><H2 CLASS="sect2" ><A NAME="references.this" ></A ><TT CLASS="literal" >$this</TT ></H2 ><P > In an object method, <TT CLASS="varname" >$this</TT > is always reference to the caller object. </P ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="language.references.unset.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="features.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Unsetting References</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="language.references.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Features</TD ></TR ></TABLE ></DIV ></BODY ></HTML >