Use static in php functions _ PHP Tutorial-php Tutorial

Source: Internet
Author: User
Tags sapi
Use static in php functions. Copy the code as follows: functionsendHeader ($ num, $ rtarrnull) {static $ sapinull; if ($ sapinull) {$ sapiphp_sapi_name ();} return $ sapi ++; when reading PW source code, we found The code is as follows:

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:

Echo sendHeader (1 )."
Echo sendHeader (2 )."
Echo sendHeader (3 )."


The code is as follows:


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: function sendHeader ($ num, $ rtarr = null) {static $ sapi = null; if ($ sapi = null) {$ sapi = php_sapi_name ();} return $ sapi ++; found when reading PW source code...

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