mysqli_poll() - 第三个参数是什么？

Question

在缺少函数原型之外的任何文档的情况下,我很难找到mysqli_poll()函数的第三个参数.

int mysqli_poll ( 
     array &$read , 
     array &$error , 
     array &$reject , 
     int $sec 
     [, int $usec ] )

看一下(C)源代码,看来用$资源填充$ reject数组......

CONN_GET_STATE((*p)->data) <= CONN_READY 
   || CONN_GET_STATE((*p)->data) == CONN_QUIT_SENT

这是否意味着与服务器的连接正在关闭/关闭？

别的什么？

是否应预先设置资源以检查是否断开连接？或者它们会自动从$ read和$ error中添加？

Answer 1

我搭建了一个测试装置：

$l1 = mysqli_connect();
$l2 = mysqli_connect();
$l3 = mysqli_connect();

$s1 = "SELECT CURTIME()";
$s2 = "SELECT * FROM";   // will error #1064
$s3 = "SELECT SLEEP(10), CURTIME()";

mysqli_query($l1, $s1, MYSQLI_ASYNC);
mysqli_query($l2, $s2, MYSQLI_ASYNC);
mysqli_query($l3, $s3, MYSQLI_ASYNC);

$started=time();

for ($x=0; $x<5; $x++) {
        $ready=$reject=$errors = array($l1, $l2, $l3);
        print "\niteration $x at t+" . (time()-$started) . "\n";
        mysqli_poll($ready, $errors, $reject, 3);
        print "ready = " . count($ready) . "\n";
        foreach($ready as $r) {
           $c=mysqli_reap_async_query($r);
           print "err=" . mysqli_error($r) . " cnt=" . count($c) . "\n";
        };
        print "errors = " . count($errors) . "\n";
        print "reject = " . count($reject) . "\n";
        sleep(4);
 }

结果（以//为前缀的注释）：

iteration 0 at t+0
ready = 1              // appears to be SELECT CURTIME()
err= cnt=1
errors = 0
reject = 0

iteration 1 at t+4
ready = 1              // appears to be SELECT * FROM
err=You have an error in your SQL syntax; check the manual that corresponds 
  to your MySQL server version for the right syntax to use near '' at line 
  1 cnt=1
errors = 0
reject = 1             // appears to be SELECT CURTIME() (results reaped)

iteration 2 at t+8
ready = 1              // appears to be SELECT SLEEP(10) despite 8 seconds elapsed
err= cnt=1
errors = 0
reject = 2             // appears to be SELECT CURTIME() + SELECT * FROM

iteration 3 at t+14
ready = 0
errors = 0
reject = 3

iteration 4 at t+21
ready = 0
errors = 0
reject = 3

即 $reject 正在填充已获得结果的链接，而不是尚未准备好轮询的链接。

尝试使用无效连接，该值将从所有数组中删除（不添加到 $reject），