Add embryonic error handling section, since we don't have one place for this.

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@337352 c90b9560-bf6c-de11-be94-00142212c4b1

language/errors.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<!-- $Revision$ -->
+<chapter xml:id="language.errors" xmlns="http://docbook.org/ns/docbook" xmlns:phd="http://www.php.net/ns/phd">
+ <title>Errors</title>
+
+ <sect1 phd:chunk="false" xml:id="language.errors.intro">
+  <title>Introduction</title>
+
+  <para>
+   Sadly, no matter how careful we are when writing our code, errors are a
+   fact of life. PHP will report errors, warnings and notices for many common
+   coding and runtime problems, and knowing how to detect and handle these
+   errors will make debugging much easier.
+  </para>
+ </sect1>
+
+ &language.errors.basics;
+ &language.errors.php7;
+</chapter>
+ 
+<!-- Keep this comment at the end of the file
+Local variables:
+mode: sgml
+sgml-omittag:t
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:1
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+sgml-default-dtd-file:"~/.phpdoc/manual.ced"
+sgml-exposed-tags:nil
+sgml-local-catalogs:nil
+sgml-local-ecat-files:nil
+End:
+vim600: syn=xml fen fdm=syntax fdl=2 si
+vim: et tw=78 syn=sgml
+vi: ts=1 sw=1
+-->

language/errors/basics.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<!-- $Revision$ -->
+
+<sect1 xml:id="language.errors.basics" xmlns="http://docbook.org/ns/docbook">
+ <title>Basics</title>
+
+ <para>
+  PHP reports errors in response to a number of internal error conditions.
+  These may be used to signal a number of different conditions, and can be
+  displayed and/or logged as required.
+ </para>
+
+ <para>
+  Every error that PHP generates includes a type. A
+  <link linkend="errorfunc.constants">list of these types</link> is available,
+  along with a short description of their behaviour and how they can be
+  caused.
+ </para>
+
+ <sect2 xml:id="language.errors.basics.handling">
+  <title>Handling errors with PHP</title>
+
+  <para>
+   If no error handler is set, then PHP will handle any errors that occur
+   according to its configuration. Which errors are reported and which are
+   ignored is controlled by the
+   <link linkend="ini.error-reporting"><parameter>error_reporting</parameter></link>
+   php.ini directive, or at runtime by calling
+   <function>error_reporting</function>. It is strongly recommended that the
+   configuration directive be set, however, as some errors can occur before
+   execution of your script begins.
+  </para>
+
+  <para>
+   In a development environment, you should always set
+   <link linkend="ini.error-reporting"><parameter>error_reporting</parameter></link>
+   to <constant>E_ALL</constant>, as you need to be aware of and fix the
+   issues raised by PHP. In production, you may wish to set this to a less
+   verbose level such as
+   <code>E_ALL &amp; ~E_NOTICE &amp; ~E_STRICT &amp; ~E_DEPRECATED</code>, but
+   in many cases <constant>E_ALL</constant> is also appropriate, as it may
+   provide early warning of potential issues.
+  </para>
+
+  <para>
+   What PHP does with these errors depends on two further php.ini directives.
+   <link linkend="ini.display-errors"><parameter>display_errors</parameter></link>
+   controls whether the error is shown as part of the script's output. This
+   should always be disabled in a production environment, as it can include
+   confidential information such as database passwords, but is often useful to
+   enable in development, as it ensures immediate reporting of issues.
+  </para>
+
+  <para>
+   In addition to displaying errors, PHP can log errors when the
+   <link linkend="ini.log-errors"><parameter>log_errors</parameter></link>
+   directive is enabled. This will log any errors to the file or syslog
+   defined by
+   <link linkend="ini.error-log"><parameter>error_log</parameter></link>. This
+   can be extremely useful in a production environment, as you can log errors
+   that occur and then generate reports based on those errors.
+  </para>
+ </sect2>
+
+ <sect2 xml:id="language.errors.basics.user">
+  <title>User error handlers</title>
+
+  <para>
+   If PHP's default error handling is inadequate, you can also handle many
+   types of error with your own custom error handler by installing it with
+   <function>set_error_handler</function>. While some error types cannot be
+   handled this way, those that can be handled can then be handled in the way
+   that your script sees fit: for example, this can be used to show a custom
+   error page to the user and then report more directly than via a log, such
+   as by sending an e-mail.
+  </para>
+ </sect2>
+</sect1>
+ 
+<!-- Keep this comment at the end of the file
+Local variables:
+mode: sgml
+sgml-omittag:t
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:1
+sgml-indent-data:t
+indent-tabs-mode:nil
+sgml-parent-document:nil
+sgml-default-dtd-file:"~/.phpdoc/manual.ced"
+sgml-exposed-tags:nil
+sgml-local-catalogs:nil
+sgml-local-ecat-files:nil
+End:
+vim600: syn=xml fen fdm=syntax fdl=2 si
+vim: et tw=78 syn=sgml
+vi: ts=1 sw=1
+-->
+

language/errors/php7.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<!-- $Revision$ -->
+
+<sect1 xml:id="language.errors.php7" xmlns="http://docbook.org/ns/docbook">
+ <title>Errors in PHP 7</title>
+
+ <para>
+  PHP 7 changes how most errors are reported by PHP. Instead of reporting
+  errors through the traditional error reporting mechanism used by PHP 5, most
+  errors are now reported by throwing <classname>Error</classname> exceptions.
+ </para>
+
+ <para>
+  As with normal exceptions, these <classname>Error</classname> exceptions
+  will bubble up until they reach the first matching
+  <link linkend="language.exceptions.catch"><literal>catch</literal></link>
+  block. If there are no matching blocks, then any default exception handler
+  installed with <function>set_exception_handler</function> will be called,
+  and if there is no default exception handler, then the exception will be
+  converted to a fatal error and will be handled like a traditional error.
+ </para>
+
+ <para>
+  As the <classname>Error</classname> hierarchy does not inherit from
+  <classname>Exception</classname>, code that uses
+  <code>catch (Exception $e) { ... }</code> blocks to handle uncaught
+  exceptions in PHP 5 will find that these <classname>Error</classname>s are
+  not caught by these blocks. Either a <code>catch (Error $e) { ... }</code>
+  block or a <function>set_exception_handler</function> handler is required.
+ </para>
+
+ <para>
+  A list of <classname>Error</classname> subclasses can be found in the
+  <link linkend="book.errorfunc">error function section</link> of the manual.
+ </para>
+</sect1>
+ 
+<!-- Keep this comment at the end of the file
+Local variables:
+mode: sgml
+sgml-omittag:t
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:1
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+sgml-default-dtd-file:"~/.phpdoc/manual.ced"
+sgml-exposed-tags:nil
+sgml-local-catalogs:nil
+sgml-local-ecat-files:nil
+End:
+vim600: syn=xml fen fdm=syntax fdl=2 si
+vim: et tw=78 syn=sgml
+vi: ts=1 sw=1
+-->
+