php裡的declare用法

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function tick_handler ()
{
echo "tick_handler() called<br>" ;
}
function tick_handler1 ()
{
echo "tick_handler1() called<br>" ;
}

register_tick_function ( ‘tick_handler‘ );
register_tick_function ( ‘tick_handler1‘ );

declare( ticks = 1 ){
$a = 1 ;

if ( $a > 0 ) {
$a += 2 ;
print( $a );
}
}
exit;

這裡首先定義了兩個函數，然後註冊到系統，隨後通過declare定義一個ticks，步長為1，作用是在declare範圍中的代碼每執行ticks次步長，就執行一次註冊的方法，方法順與註冊的順序一致。

所以上面的執行結果是：

tick_handler() called
tick_handler1() called
tick_handler() called
tick_handler1() called
3tick_handler() called
tick_handler1() called
tick_handler() called
tick_handler1() called
tick_handler() called
tick_handler1() called
tick_handler() called
tick_handler1() called

這個方法可以測試執行代碼的處理時間。