socket_select立即返回false buth沒有錯誤代碼

Question

我與socket_select玩，但有一個主機，這個功能確實奇怪的事情：立即

• 的回報，而不是等待5秒
• 返回false，表示一些錯誤
• 但socket_last_error()返回0（成功）。

此服務器的phpinfo()：http://jsfiddle.net/Lmrfe/embedded/result/

$server = socket_create(AF_UNIX, SOCK_STREAM, 0); 
$r = socket_bind($server, '/some/file/somewhere'); 
$r = socket_listen($server); 
// none of the above socket_* returns false 

$t = microtime(true); 
socket_clear_error(); 

$read = array($server); $write = null; $except = null; 
$read = array($server); $write = array(); $except = array(); 
$read = array(); $write = array(); $except = array(); 
$read = null; $write = null; $except = null; 

$changed = socket_select($read, $write, $except, 5,0); 
$changed = socket_select($read, $write, $except, null); 
$changed = socket_select($read, $write, $except, 5000000); 
$changed = socket_select($read, $write, $except, 5000000, 0); 
$changed = socket_select($read, $write, $except, 5000000, 5000000); 

/* Results: 

    microtime(true) - $t == almost zero 

    $changed === false 

    socket_last_error() === 0 
    socket_strerror(socket_last_error()) === Success 

    $read === array(1) { 
    [0]=> 
    resource(2) of type (Socket) 
    } 
    $write === NULL 
    $except === NULL 
*/ 

$s = socket_read($server, 1024, PHP_BINARY_READ); 
// $s === false 

發生了什麼事嗎？

更新測試腳本：仍然運行在瞬間：

header('Content-Type: text/plain; charset=utf-8'); 
error_reporting(-1); 

for($i = 0; $i < 4; $i++){ 
for($j = 0; $j < 5; $j++){ 
    echo "\n\n\n\n\n[i,j]=[{$i},{$j}]\n"; 

    $socket = socket_create(AF_UNIX, SOCK_STREAM, 0); 
    var_dump('socket_create', $socket); echo "\n"; if($socket === false) continue; 

    $socket_file = dirname(__FILE__)."/test_socket_i{$i}_j{$j}"; 
    if(file_exists($socket_file)) unlink($socket_file); 

    $r = socket_bind($socket, $socket_file); 
    var_dump('socket_bind', $r); echo "\n"; if($r === false) continue; 

    $r = socket_listen($socket); 
    var_dump('socket_listen', $r); echo "\n"; if($r === false) continue; 

    $t = microtime(true); 
    socket_clear_error(); 

    if($i==0){ $read = null;    $write = null; $except = null; } 
    if($i==1){ $read = array();   $write = array(); $except = array(); } 
    if($i==2){ $read = array($socket); $write = null; $except = null; } 
    if($i==3){ $read = array($socket); $write = array(); $except = array(); } 

    if($j==0){ $changed = socket_select($read, $write, $except, 5,0); } // 5 seconds 
    if($j==1){ $changed = socket_select($read, $write, $except, null); } // forever 
    if($j==2){ $changed = socket_select($read, $write, $except, 5000000); } 
    if($j==3){ $changed = socket_select($read, $write, $except, 5000000, 0); } 
    if($j==4){ $changed = socket_select($read, $write, $except, 5000000, 5000000); } 

    var_dump('•socket_select returned:', $changed);echo "\n"; 
    var_dump('•$read/$write/$except:',$read,$write,$except);echo "\n"; 
    var_dump('•error:', socket_last_error(), socket_strerror(socket_last_error()));echo "\n"; 
    var_dump('time: ', microtime(true) - $t);echo "\n";    // almost zero 
}} 

Answer 1

如果你遇到了這個錯誤，你可以使用類似的東西圍繞工作吧：

$socket_select_timeout_seconds = 5; 

while(true){ 
    $time_start = microtime(true); 
    $c = socket_select($r,$w,$e, $socket_select_timeout_seconds); 

    if(/* something happened */){ 
    // handle socket events 
    }else if(microtime(true) - $time_start < 0.01){ 
    // nothing happened, but buggy socket_select didn't wait 
    // wait manually 
    usleep($socket_select_timeout_seconds * 1000000); 
    } 

} 

Answer 2

你可能想使用的，而不是插座stream_ *功能。

流功能更通用，是PHP核心的一部分，而Socket支持需要安裝。流功能給你基本上更多的控制權。

http://www.php.net/manual/en/intro.stream.php

Answer 3

檢查此 http://php.net/manual/en/function.socket-select.php

由於在當前Zend引擎的限制，不可能通過一恆定改性劑像NULL直接作爲參數傳遞給一個函數，它預計此參數來通過參考傳遞。而是使用一個臨時變量或表達式最左邊的部件是一個臨時變量：

所以問題是，你是初始化$write = null

Answer 4

由於@Amez指出你不應該傳遞null值來選擇。相反，對於未使用的socket_select()參數創建一個空數組：

$read = array($server); 
$write = array(); 
$except = array(); 
$changed = socket_select($read, $write, $except, 5,0); 

我剛剛在Python中同樣的問題絆倒了（我不知道爲什麼PHP/Python將不會簡單地替換空值作爲內部機智空數組對於選擇這當然似乎是預期的行爲）。