php_doc.php

      </programlisting>
     </example>
    </para>
+  
+   <sect2 xml:id="functions.scalar-type-declaration">
+    <title>Type Declaration</title>
+    <note>
+     <para>
+      Type declaration is also known as Type Hinting.
+     </para>
+    </note>
+    <para>
+     PHP 7 introduces scalar type declaration. Functions are now able to force parameters
+     to be <type>string</type>, <type>int</type>, <type>float</type> or <type>bool</type>.
+     By default all PHP Files are in weakly typed mode. 
+     To enable strict type checking, declare(strict_types=1) directive must be the first
+     statement in the file. strict_types has two options, 1 for strict type
+     checking and 0 for weak type checking. This only affects the file this is stated in and not
+     files either included in this file or other files that include this file.
+     Whether or not the function being called was declared in a file that uses strict or weak 
+     type checking is irrelevant. The type checking mode depends on the file where the function is called from.
+    </para>
+    <para>
+     <example>
+      <title>Scalar Type Parameters examples</title>
+       <programlisting role="php">
+<![CDATA[
+<?php
+declare(strict_types=1); // Fatal error if this is not the first statement
  
+foo(); // strictly type-checked function call
+
+function foobar() {
+    foo(); // strictly type-checked function call
+}
+ 
+class baz {
+    function foobar() {
+        foo(); // strictly type-checked function call
+    }
+}
+
+
+/*
+ If this is file 2 and file 1 includes this file,
+ num() function calls from file 1 are not strictly type-checked unless
+ file 1 has set strict_types=1
+*/
+function num(int $a) {
+    return $a;
+}
+
+]]>
+  </programlisting>
+  <programlisting role="php">
+<![CDATA[
+<?php // file 1
+declare(strict_types=1);
+
+/*
+ file 1 - strictly type checked
+ file 2 - weakly type checked
+*/
+
+include 'file2.php';
+
+a(1); // strictly type checked
+b(1); // strictly type checked
+
+function a(int $a) {
+    return $a;
+}
+
+?>
+
+<?php // file 2
+
+b(1); // weakly type checked
+
+function b(int $a) {
+    return $a;
+}
+
+?>
+
+]]>
+  </programlisting>
+  <programlisting role="php">
+<![CDATA[
+<?php // file 1
+
+/*
+ file 1 - weakly type checked
+ file 2 - strictly type checked
+*/
+
+include 'file2.php';
+
+a(1); // weakly type checked
+b(1); // weakly type checked
+
+function a(int $a) {
+    return $a;
+}
+
+
+?>
+
+<?php // file 2
+declare(strict_types=1);
+
+b(1); // strictly type checked
+
+function b(int $a) {
+    return $a;
+}
+
+?>
+
+]]>
+      </programlisting>
+     </example>
+    </para>
+   </sect2>
+

!Y@ at@Y!