檢查exec（）是否成功運行

Question

我一直在試圖讓知道知道如果PHP中的exec()命令執行成功與否，所以我可以相應地回覆某些消息。 我試了下面這段代碼，但它的問題是，exec()是否成功運行，它總是echo "PDF not created"，並從未成功創建回聲pdf。請讓我知道我可以在EXEC的執行（執行檢查），這樣我就可以相應地迴響消息 感謝，

<?php 
if (exec('C://abc//wkhtmltopdf home.html sample.pdf')) 
echo "PDF Created Successfully"; 
else 
echo "PDF not created"; 
?> 

Answer 1

根據PHP的exec quickref，你可以通過指針獲得的輸出和狀態命令。

<?php 
exec('C://abc//wkhtmltopdf home.html sample.pdf', $output, $return); 

// Return will return non-zero upon an error 
if (!$return) { 
    echo "PDF Created Successfully"; 
} else { 
    echo "PDF not created"; 
} 
?> 

如果要列舉可能出現的錯誤，你可以在hiteksoftware

Answer 2

找到代碼在一個簡單的例子：

$ip = "192.168.0.2"; 
$exec = exec("ping -c 3 -s 64 -t 64 ".$ip, $output, $return); 
echo $exec; 
echo "<br />----------------<br />"; 
print_r($output); 
echo "<br />----------------<br />"; 
print_r($return); 

在無法ping或錯誤的情況下。 （一）

---------------- 
Array ([0] => PING 192.168.0.2 (192.168.0.2) 64(92) bytes of data. [1] => [2] => --- 192.168.0.2 ping statistics --- [3] => 3 packets transmitted, 0 received, 100% packet loss, time 2016ms [4] =>) 
---------------- 
1 

在成功（ZERO）

rtt min/avg/max/mdev = 4.727/18.262/35.896/13.050 ms 
---------------- 
Array ([0] => PING 192.168.0.2 (192.168.0.2) 64(92) bytes of data. [1] => 72 bytes from 192.168.0.2: icmp_req=1 ttl=63 time=14.1 ms [2] => 72 bytes from 192.168.0.2: icmp_req=2 ttl=63 time=35.8 ms [3] => 72 bytes from 192.168.0.2: icmp_req=3 ttl=63 time=4.72 ms [4] => [5] => --- 192.168.0.2 ping statistics --- [6] => 3 packets transmitted, 3 received, 0% packet loss, time 2003ms [7] => rtt min/avg/max/mdev = 4.727/18.262/35.896/13.050 ms) 
---------------- 
0 

Answer 3

正確的方法是，以檢查$ return_var沒有設置爲零，因爲它只是設置爲零時的情況下，它是成功的。在某些情況下，exec可能會失敗，並且return_var沒有設置爲任何值。例如。如果服務器在執行期間耗盡了磁盤空間。

<?php 
exec('C://abc//wkhtmltopdf home.html sample.pdf', $output, $return_var); 
if($return_var !== 0){ // exec is successful only if the $return_var was set to 0. !== means equal and identical, that is it is an integer and it also is zero. 
    echo "PDF not created"; 
} 
else{ 
    echo "PDF Created Successfully"; 
} 

?> 

注意：不要初始化$ return_var零