<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >defined</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="Manual do PHP" HREF="index.html"><LINK REL="UP" TITLE="Miscelânea" HREF="ref.misc.html"><LINK REL="PREVIOUS" TITLE="define" HREF="function.define.html"><LINK REL="NEXT" TITLE="die" HREF="function.die.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" 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" >Manual do PHP</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.define.html" ACCESSKEY="P" >Anterior</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.die.html" ACCESSKEY="N" >Próxima</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.defined" ></A >defined</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN121232" ></A ><P > (PHP 3, PHP 4, PHP 5)</P >defined -- Confere se uma constante existe </DIV ><DIV CLASS="refsect1" ><A NAME="AEN121235" ></A ><H2 >Descrição</H2 >bool <B CLASS="methodname" >defined</B > ( string name )<BR ></BR ><P > Retorna <TT CLASS="constant" ><B >TRUE</B ></TT > se a constante dada pelo parâmetro <CODE CLASS="parameter" >name</CODE > já foi definida, em outro caso <TT CLASS="constant" ><B >FALSE</B ></TT >. </P ><P > <TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN121248" ></A ><P ><B >Exemplo 1. Conferindo Constantes</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br /></font><font color="#FF8000">// Note que deve estar entre apostrofros, este<br />// exemplo esta conferindo se existe uma constante com o nome de CONSTANT<br /></font><font color="#007700">if (</font><font color="#0000BB">defined</font><font color="#007700">(</font><font color="#DD0000">'CONSTANT'</font><font color="#007700">)){<br /> echo </font><font color="#0000BB">CONSTANT</font><font color="#007700">;<br /> }<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE > </P ><DIV CLASS="note" ><BLOCKQUOTE CLASS="note" ><P ><B >Nota: </B > Se você este querendo ver se um variável existe use <A HREF="function.isset.html" ><B CLASS="function" >isset()</B ></A > porque a função <B CLASS="function" >defined()</B > aplica-se somente a <A HREF="language.constants.html" >constantes</A >. Se você quiser saber se uma função existe use <A HREF="function.function-exists.html" ><B CLASS="function" >function_exists()</B ></A >. </P ></BLOCKQUOTE ></DIV ><P > Veja também <A HREF="function.define.html" ><B CLASS="function" >define()</B ></A >, <A HREF="function.constant.html" ><B CLASS="function" >constant()</B ></A >, <A HREF="function.get-defined-constants.html" ><B CLASS="function" >get_defined_constants()</B ></A >, <A HREF="function.function-exists.html" ><B CLASS="function" >function_exists()</B ></A >, e a seção sobre <A HREF="language.constants.html" >Constantes</A >. </P ></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="function.define.html" ACCESSKEY="P" >Anterior</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Principal</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.die.html" ACCESSKEY="N" >Próxima</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >define</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.misc.html" ACCESSKEY="U" >Acima</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >die</TD ></TR ></TABLE ></DIV ></BODY ></HTML >