Use static variables in php functions

The code is as follows:	Copy code
Function sendHeader ($ num, $ rtarr = null) {     Static $ sapi = null; If ($ sapi = null) {         $ Sapi = php_sapi_name (); }     Return $ sapi ++;

When reading the PW source code, I found that the setHeader () function uses the static keyword. It is strange that it has never been used before.

Static is used in the function. After a variable is declared, if this function is called again, it will continue at the initial value. For example, $ sapi will accumulate here.

The code is as follows:	Copy code
? Echo sendHeader (1). "<br> "; Echo sendHeader (2). "<br> "; Echo sendHeader (3). "<br> "; Output: ? Apache2handler Apache2handles Apache2handlet

It is a bit similar to global, but the difference is the scope. Static can only act on this function.

A little interesting. In-depth research is required.

 

The code is as follows:	Copy code
Class test { Public static function (){} Public function B (){} } $ Obj = new test;

Call code

The code is as follows:	Copy code
Test: (); $ Obj-> (); $ Obj-> B ();

Another important feature of variable range is static variable ). Static variables only exist in local function domains, but their values are not lost when the program runs out of this scope.

Example of static variables

The code is as follows:	Copy code
<? Php Function test ()    { Static $ w3sky = 0; Echo $ w3sky; $ W3sky ++;    } ?>

Now, every time you call the test () function, the value of $ w3sky is output and added with one.

For more details, see: http://www.111cn.net/phper/php/php-static.htm