Instructions for using static in PHP functions _php tips

Copy Code code as follows:

function Sendheader ($num, $rtarr = null) {
static $SAPI = null;
if ($sapi = = null) {
$sapi = Php_sapi_name ();
}
return $SAPI + +;

Look at the PW source code found in the SetHeader () function using the static keyword, very strange, has not been used before.

Static is used inside a function, once a variable is declared, if the function is called again, it will continue in the initial value, such as $sapi here.

Copy Code code as follows:

echo Sendheader (1). " <br> ";
Echo Sendheader (2). " <br> ";
Echo Sendheader (3). " <br> ";

Output

Copy Code code as follows:

Apache2handler
Apache2handles
Apache2handlet

It's a bit like global, but the scope is different. Static can only work on this function.

It's kind of interesting. Needs to be studied in depth.