Instructions on the role of the at @ symbol in php

Instructions on the role of the at @ symbol in php_PHP tutorial

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Release： 2016-07-13 17:16:12

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I believe that many new PHP users like me have been frustrated by this problem when they were learning PHP. What exactly does the @(at) symbol do?

Once, I downloaded someone else's source code and looked at it. I saw countless @ marks, and I thought they were comments at first; later I found that the statements after @ will also be executed. I'm confused, what is this mark for?....

As the study continues to deepen, I finally understand. The function of this mark is somewhat similar to the ignored error "on error resume next" in ASP. Their functions are the same. When the PHP interpreter encounters a statement starting with @, regardless of whether the statement in this line is executed successfully, it will continue to execute subsequent statements without reporting an error. But please note that the @(at) mark only works on the current line.

I hope the question about @(at) ends here.

eg. The following sentence will definitely report an error

Error code

The code is as follows

代码如下

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$sql = mysql_connect(*);
?>

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$sql = mysql_connect(*);

代码如下	复制代码
@$sql = mysql_connect(*); echo "我一直在执行"; ?>

代码如下	复制代码
@$page=$_GET['page']?intval($_GET['page']):1;

However, if we add the @(at) mark, the error will not be reported and execution will continue.

No error code

The code is as follows

代码如下	复制代码
$conn = mysqli_conncet("q","w","e","r");

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代码如下	复制代码
@$conn = mysqli_conncet("q","w","e","r");

@$sql = mysql_connect(*);

echo "I have been executing";

Continue executing the code below.

The code is as follows

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@$page=$_GET['page']?intval($_GET['page']):1; This sentence is to get the value of the page keyword from the URL, such as "index.php?page=5", then $page will get 5. But if there is an error, for example, there is no page keyword after "index.php", and if $_GET['page'] does not exist, an error will be reported. At this time, you can ignore this small error with @. Another example:

The code is as follows

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$conn = mysqli_conncet("q","w","e","r"); This will input error information about connecting to the database.

The code is as follows

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@$conn = mysqli_conncet("q","w","e","r"); If you add @ in front of $conn, you can prevent it from outputting error messages.