Using static variables in php functions_PHP tutorial

This article will briefly introduce the use of static variables in PHP functions. Students who need to know more can refer to it.

The code is as follows

代码如下	复制代码
function sendHeader($num, $rtarr = null) {     static $sapi = null;     if ($sapi === null) {         $sapi = php_sapi_name();     }     return $sapi++;

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function sendHeader($num, $rtarr = null)

{ 

static $sapi = null;

代码如下	复制代码
?echo sendHeader(1)." "; echo sendHeader(2)." "; echo sendHeader(3)." "; output: ?apache2handler apache2handles apache2handlet

if ($sapi === null)

{    

$sapi = php_sapi_name();

} 

return $sapi++;

代码如下	复制代码
class test { public static function a(){} public function b(){} } $obj = new test;

代码如下	复制代码
test::a(); $obj->a(); $obj->b();

When looking at the PW source code, I found that the static keyword is used in the setHeader() function, which is very strange. It has never been used in this way before.

Static is used in functions. After declaring a variable once, if the function is called again, it will continue from the initial value. For example, $sapi will be accumulated.

output:

The code is as follows

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代码如下	复制代码
function test()    {    static $w3sky = 0;    echo $w3sky;    $w3sky++;    }    ?>

?echo sendHeader(1)."
";

echo sendHeader(2)."
";
echo sendHeader(3)."
";

?apache2handler

apache2handles

apache2handlet It is similar to global, but the difference is the scope. static can only be used on this function. Interesting. Needs further research.

The code is as follows

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class test { public static function a(){}

public function b(){}

} $obj = new test; Call code

The code is as follows

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test::a(); $obj->a(); $obj->b(); Another important feature of variable scope is static variables. Static variables only exist in the local function scope, but their values ​​are not lost when the program execution leaves this scope Example Example of using static variables

The code is as follows

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function test() { static $w3sky = 0; echo $w3sky; $w3sky++; } ?> Now, each call to the test() function will output the value of $w3sky and increment it by one. For more details, please see: http://www.bKjia.c0m/phper/php/php-static.htm http://www.bkjia.com/PHPjc/629126.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/629126.htmlTechArticleThis article briefly introduces the usage of static variables in php functions. Students who need to know more can refer to it. one time. The code is as follows Copy code function sendHeader($num, $rtarr =...