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    <p>The Strict Standards part is because <code>a::read()</code> is being called in a static context with <code>::</code>. After declaring <code>$a</code> as a class instance of <code>A</code>, you should call the <code>read()</code> method on the variable using the <code>-&gt;</code> operator:</p> <pre><code>// Proper non-static method call $a = new A(); $a-&gt;read(); </code></pre> <p>In the class definition, <code>$foo</code> is declared as a private property, but without the <code>static</code> keyword. It is then referred to in static context using the <code>::</code> operator instead of the <code>-&gt;</code>. The proper way to access it would beL</p> <pre><code>// Proper reference to non-static $foo function read() { echo $this-&gt;foo; } </code></pre> <p>Now what does <code>static</code> mean anyway? Static methods and properties refer to class methods and properties that are shared by all current and future class instances. If <code>A::$foo</code> had been declared as:</p> <pre><code>private static $foo; </code></pre> <p>then there would be only the one <code>$foo</code> for all of class <code>A</code> in your code. Changing <code>$foo</code> would affect all instances of class <code>A</code>, and <code>$foo</code> can be accessed without even creating an instance of the class (like <code>new A();</code>)</p> <p>Likewise, static methods can be called without creating an instance of the class because they do not modify class properties that are not also static.</p> <pre><code>// Static method call: A::read(); </code></pre> <p>To declare properties and methods as <code>static</code>, just add the <code>static</code> keyword:</p> <pre><code>// Property private static $foo; // Method public static function foo() {} </code></pre> <p><strong>EDIT for more examples</strong>:</p> <pre><code>class A { // Private property (non-static) private $foo; // Public property (static) public static $bar = 12345; // Public (non-static) function to access private $foo public function getFoo() { return $this-&gt;foo; } // Public (non-static) function to set private $foo public function setFoo($newfoo) { $this-&gt;foo = $newfoo; } // Static function public static function incrementBar() { self::$bar++; } } </code></pre> <p>Now see it in action:</p> <pre><code>// We haven't created any class instances yet (with the 'new' operator) // But we can access the static properties &amp; functions: echo A::$bar . " "; // prints 12345 A::incrementBar(); echo A::$bar . "\n"; // prints 12346 // Now we'll start working with class instances. // Create 2 instances of class A $a = new A(); $a-&gt;setFoo(8888); $b = new A(); $b-&gt;setFoo(9999); // It's a violation of strict standards to call getFoo() statically // And it's meaningless to do so, because $foo only exists inside a class instance! // Can't do this... Issues a strict warning since we're calling non-static getFoo() statically //echo A::getFoo(); // But we can call getFoo() on the class instances: echo $a-&gt;getFoo() . " " . $b-&gt;getFoo() . "\n"; // Prints 8888 9999 // Remember $bar was 12346... echo $a::$bar . " " . $b::$bar . "\n"; // Prints 12346 12346 // Now modify the static property $bar again // This affects all class instances. A::incrementBar(); echo $a::$bar . " " . $b::$bar . "\n"; // Prints 12347 12347 </code></pre> <p>I stuffed this whole thing into the codepad as well: <a href="http://codepad.viper-7.com/tV6omK" rel="noreferrer">http://codepad.viper-7.com/tV6omK</a></p> <p>The book you're reading must not be paying attention to strict standards. If a non-static function does not attempt to access/modify a non-static property, you can call it statically successfully, but it WILL issue a strict warning. If the non-static function does modify or access a non-static property with <code>$this-&gt;property</code>, it will be a fatal error. You can't do that.</p> <p>In PHP's <code>error_reporting</code>, the setting of <code>E_ALL</code> for show all errors actually does not include strict warnings. That has to be done with <code>E_ALL &amp; E_STRICT</code>.</p>
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    1. POPHP: Why am I getting errors about static properties?
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    1. COI'm sorry, but I don't understand this at all. Can you actually post changes to a codepad or a codeblock, completely, and show which lines you've changed? I'm trying to access a static method, but I can't seem to do it statically or non-statically.
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    2. COIf I am understanding you correctly, they must both either be static or non-static, but if I want to restrict the scope for properties only, I have to do so by setting the properties I want restricted to private or protected. Then, I can access properties through methods, but I cannot access the properties directly, which--as you apparently read into my question--is what I was trying to do.
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    3. CO@Fohsap I added a big new example to illustrate.
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