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><A
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>Apêndice C. Migrating from PHP 4 to PHP 5</TD
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><H1
CLASS="section"
><A
NAME="migration5.incompatible"
>Backward Incompatible Changes</A
></H1
><P
> Although most existing PHP 4 code should work without changes, you should
pay attention to the following backward incompatible changes:
</P
><P
></P
><UL
><LI
><P
> There are some <A
HREF="reserved.html#reserved.keywords"
>new reserved
keywords</A
>.
</P
></LI
><LI
><P
> <A
HREF="function.strrpos.html"
><B
CLASS="function"
>strrpos()</B
></A
> and <A
HREF="function.strripos.html"
><B
CLASS="function"
>strripos()</B
></A
> now use
the entire string as a needle.
</P
></LI
><LI
><P
> Illegal use of string offsets causes <TT
CLASS="constant"
><B
>E_ERROR</B
></TT
> instead
of <TT
CLASS="constant"
><B
>E_WARNING</B
></TT
>. An example illegal use is:
<TT
CLASS="literal"
>$str = 'abc'; unset($str[0]);</TT
>.
</P
></LI
><LI
><P
> <A
HREF="function.array-merge.html"
><B
CLASS="function"
>array_merge()</B
></A
> was changed to accept only arrays. If a
non-array variable is passed, a <TT
CLASS="constant"
><B
>E_WARNING</B
></TT
> will be
thrown for every such parameter. Be careful because your code may start
emitting <TT
CLASS="constant"
><B
>E_WARNING</B
></TT
> out of the blue.
</P
></LI
><LI
><P
> PATH_TRANSLATED server variable is no longer set implicitly under
Apache2 SAPI in contrast to the situation in PHP 4, where it is set to
the same value as the SCRIPT_FILENAME server variable when it is not
populated by Apache. This change was made to comply with the <A
HREF="http://hoohoo.ncsa.uiuc.edu/cgi/"
TARGET="_top"
>CGI specification</A
>. Please refer to <A
HREF="http://bugs.php.net/23610"
TARGET="_top"
>bug #23610</A
> for further information,
and see also the <A
HREF="reserved.variables.html#reserved.variables.server"
> $_SERVER['PATH_TRANSLATED']</A
> description in the manual. This issue
also affects PHP versions >= 4.3.2.
</P
></LI
><LI
><P
> The <TT
CLASS="constant"
><B
>T_ML_COMMENT</B
></TT
> constant is no longer defined by
the <A
HREF="ref.tokenizer.html"
>Tokenizer</A
> extension. If
error_reporting is set to <TT
CLASS="constant"
><B
>E_ALL</B
></TT
>, PHP will
generate a notice. Although the <TT
CLASS="constant"
><B
>T_ML_COMMENT</B
></TT
> was
never used at all, it was defined in PHP 4. In both PHP 4 and PHP 5
// and /* */ are resolved as the <TT
CLASS="constant"
><B
>T_COMMENT</B
></TT
>
constant. However the PHPDoc style comments /** */, which starting PHP
5 are parsed by PHP, are recognized as <TT
CLASS="constant"
><B
>T_DOC_COMMENT</B
></TT
>.
</P
></LI
><LI
><P
> $_SERVER should be populated with argc and argv if <A
HREF="ini.core.html#ini.variables-order"
>variables_order</A
> includes "S". If
you have specifically configured your system to not create $_SERVER,
then of course it shouldn't be there. The change was to always make argc
and argv available in the CLI version regardless of the <A
HREF="ini.core.html#ini.variables-order"
>variables_order</A
> setting. As in,
the CLI version will now always populate the global $argc and $argv
variables.
</P
></LI
><LI
><P
> An object with no properties is no longer considered "empty".
</P
></LI
><LI
><P
> In some cases classes must be declared before use. It only happens if
some of the new features of PHP 5 (such as <A
HREF="language.oop5.interfaces.html"
>interfaces</A
>) are used.
Otherwise the behaviour is the old.
</P
></LI
><LI
><P
> <A
HREF="function.get-class.html"
><B
CLASS="function"
>get_class()</B
></A
>, <A
HREF="function.get-parent-class.html"
><B
CLASS="function"
>get_parent_class()</B
></A
>
and <A
HREF="function.get-class-methods.html"
><B
CLASS="function"
>get_class_methods()</B
></A
> now return the name of the
classes/methods as they were declared (case-sensitive) which may lead to
problems in older scripts that rely on the previous behaviour (the
class/method name was always returned lowercased). A possible solution
is to search for those functions in all your scripts and use
<A
HREF="function.strtolower.html"
><B
CLASS="function"
>strtolower()</B
></A
>.
</P
><P
> This case sensitivity change also applies to the
<A
HREF="language.constants.predefined.html"
>magical predefined
constants</A
> <TT
CLASS="constant"
><B
>__CLASS__</B
></TT
>,
<TT
CLASS="constant"
><B
>__METHOD__</B
></TT
>, and <TT
CLASS="constant"
><B
>__FUNCTION__</B
></TT
>.
The values are returned exactly as they're declared (case-sensitive).
</P
></LI
><LI
><P
> <A
HREF="function.ip2long.html"
><B
CLASS="function"
>ip2long()</B
></A
> now returns <TT
CLASS="constant"
><B
>FALSE</B
></TT
> when an invalid IP
address is passed as argument to the function, and no longer
<TT
CLASS="literal"
>-1</TT
>.
</P
></LI
><LI
><P
> If there are functions defined in the included file, they can be used in the
main file independent if they are before <A
HREF="function.return.html"
><B
CLASS="function"
>return()</B
></A
> or after.
If the file is included twice, PHP 5 issues fatal error because functions
were already declared, while PHP 4 doesn't complain about it.
It is recommended to use <A
HREF="function.include-once.html"
><B
CLASS="function"
>include_once()</B
></A
> instead of
checking if the file was already included and conditionally return inside
the included file.
</P
></LI
><LI
><P
> <A
HREF="function.include-once.html"
><B
CLASS="function"
>include_once()</B
></A
> and <A
HREF="function.require-once.html"
><B
CLASS="function"
>require_once()</B
></A
>
first normalize the path of included file on Windows so that including
A.php and a.php include the file just once.
</P
></LI
></UL
><P
> <TABLE
WIDTH="100%"
BORDER="0"
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CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN275835"
></A
><P
><B
>Exemplo C-1. <A
HREF="function.strrpos.html"
><B
CLASS="function"
>strrpos()</B
></A
> and <A
HREF="function.strripos.html"
><B
CLASS="function"
>strripos()</B
></A
> now
use the entire string as a needle</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br />var_dump</font><font color="#007700">(</font><font color="#0000BB">strrpos</font><font color="#007700">(</font><font color="#DD0000">'ABCDEF'</font><font color="#007700">,</font><font color="#DD0000">'DEF'</font><font color="#007700">)); </font><font color="#FF8000">//int(3)<br /><br /></font><font color="#0000BB">var_dump</font><font color="#007700">(</font><font color="#0000BB">strrpos</font><font color="#007700">(</font><font color="#DD0000">'ABCDEF'</font><font color="#007700">,</font><font color="#DD0000">'DAF'</font><font color="#007700">)); </font><font color="#FF8000">//bool(false)<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN275841"
></A
><P
><B
>Exemplo C-2. An object with no properties is no longer considered "empty"</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br /></font><font color="#007700">class </font><font color="#0000BB">test </font><font color="#007700">{ }<br /></font><font color="#0000BB">$t </font><font color="#007700">= new </font><font color="#0000BB">test</font><font color="#007700">();<br /><br /></font><font color="#0000BB">var_dump</font><font color="#007700">(empty(</font><font color="#0000BB">$t</font><font color="#007700">)); </font><font color="#FF8000">// echo bool(false)<br /><br /></font><font color="#007700">if (</font><font color="#0000BB">$t</font><font color="#007700">) {<br /> </font><font color="#FF8000">// Will be executed<br /></font><font color="#007700">}<br /></font><font color="#0000BB">?></font>
</font>
</code></TD
></TR
></TABLE
></DIV
></TD
></TR
></TABLE
>
</P
><P
> <TABLE
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
CLASS="EXAMPLE"
><TR
><TD
><DIV
CLASS="example"
><A
NAME="AEN275845"
></A
><P
><B
>Exemplo C-3. In some cases classes must be declared before used</B
></P
><TABLE
BORDER="0"
BGCOLOR="#E0E0E0"
CELLPADDING="5"
><TR
><TD
><code><font color="#000000">
<font color="#0000BB"><?php<br /><br /></font><font color="#FF8000">//works with no errors:<br /></font><font color="#0000BB">$a </font><font color="#007700">= new </font><font color="#0000BB">a</font><font color="#007700">();<br />class </font><font color="#0000BB">a </font><font color="#007700">{<br />}<br /><br /><br /></font><font color="#FF8000">//throws an error:<br /></font><font color="#0000BB">$a </font><font color="#007700">= new </font><font color="#0000BB">b</font><font color="#007700">();<br /><br /></font><font color="#0000BB">interface c</font><font color="#007700">{<br />}<br />class </font><font color="#0000BB">b implements c </font><font color="#007700">{<br />} <br /><br /></font><font color="#0000BB">?></font>
</font>
</code></TD
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>
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