Remove default value for limit and document zero limit.

Bug #47546, #47727 and related to #47560


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@278167 c90b9560-bf6c-de11-be94-00142212c4b1

reference/strings/functions/explode.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="iso-8859-1"?>
-<!-- $Revision: 1.19 $ -->
+<!-- $Revision: 1.20 $ -->
 <refentry xmlns="http://docbook.org/ns/docbook" xml:id="function.explode">
  <refnamediv>
   <refname>explode</refname>
@@ -12,7 +12,7 @@
    <type>array</type><methodname>explode</methodname>
    <methodparam><type>string</type><parameter>delimiter</parameter></methodparam>
    <methodparam><type>string</type><parameter>string</parameter></methodparam>
-   <methodparam choice="opt"><type>int</type><parameter>limit</parameter><initializer>-1</initializer></methodparam>
+   <methodparam choice="opt"><type>int</type><parameter>limit</parameter></methodparam>
   </methodsynopsis>
   <para>
    Returns an array of strings, each of which is a substring of
@@ -45,7 +45,7 @@
      <term><parameter>limit</parameter></term>
      <listitem>
       <para>
-       If <parameter>limit</parameter> is set, the returned array will contain
+       If <parameter>limit</parameter> is set and positive, the returned array will contain
        a maximum of <parameter>limit</parameter> elements with the last
        element containing the rest of <parameter>string</parameter>.
       </para>
@@ -53,6 +53,9 @@
        If the <parameter>limit</parameter> parameter is negative, all components
        except the last -<parameter>limit</parameter> are returned.
       </para>
+      <para>
+       If the <parameter>limit</parameter> parameter is zero, then this is treated as 1.
+      </para>
      </listitem>
     </varlistentry>
    </variablelist>