php call_user_func function-PHP Tutorial-php.cn

php call_user_func function

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Release： 2016-07-29 09:13:02

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1. Function description

　Call the callback function. Prototype: mixed call_user_func ( callable callback[ ,mix edparameter [, mixed $… ]] ). The first parameter callback is the callback function being called, and the remaining parameters are the parameters of the callback function. There can be multiple parameters or an array.
Parameters cannot be references, but references can be passed through arrays. Here is an example:

<code><span><?php</span><span><span>function</span><span>addone</span><span>(&<span>$num</span>)</span> {</span><span>$num</span> ++; 
}

<span>$num</span> = <span>0</span>;

call_user_func(<span>'addone'</span>, <span>$num</span>);
<span>echo</span><span>"num : "</span> . <span>$num</span> . <span>"\n"</span>;

call_user_func_array(<span>'addone'</span>, <span>array</span>(&<span>$num</span>) );
<span>echo</span><span>"num : "</span> . <span>$num</span> . <span>"\n"</span>;

<span>?></span></code>

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Output:
0
1
Return value: Return the return value of the callback function, or FALSE if there is an error.

2. Example

Usage of namespace.

<code><span><?php</span><span>namespace</span><span>Foobar</span>;

<span><span>class</span><span>Foo</span> {</span><span>static</span><span>public</span><span><span>function</span><span>test</span><span>()</span> {</span><span>print</span><span>"Hello world!\n"</span>;
    }
}

call_user_func(<span>__NAMESPACE__</span> .<span>'\Foo::test'</span>); 
call_user_func(<span>array</span>(<span>__NAMESPACE__</span> .<span>'\Foo'</span>, <span>'test'</span>)); 

<span>?></span></code>

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Call a method in a class

<code><span><?php</span><span><span>class</span><span>myclass</span> {</span><span>static</span><span><span>function</span><span>test</span><span>()</span>
    {</span><span>echo</span><span>"Hello world!\n"</span>;
    }
}

<span>$classname</span> = <span>"myclass"</span>;

call_user_func(<span>array</span>(<span>$classname</span>, <span>'test'</span>));

<span>$myobject</span> = <span>new</span> myclass();

call_user_func(<span>array</span>(<span>$myobject</span>, <span>'test'</span>));

<span>?></span></code>

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