PHP variable reference Analysis of reference passing precautions for PHP function value transfer

The example in this article describes the precautions for passing by reference when passing values ​​in PHP functions. Share it with everyone for your reference, the details are as follows:

Strict standards: Only variables should be passed by reference

I found this sentence in the online information:

This problem will occur in php5.3 and above versions, and it should be the same It is related to the configuration of PHP. As long as you split this sentence into two sentences, there will be no problem. Because the parameters of array_walk are passed by reference, only specific variables can be passed by default in version 5.3 and above, and values ​​cannot be returned through functions. Of course you can also modify error_reporting = E_ALL | E_STRICT in php.ini, but this does not comply with the specification after all.

$suffix = array_pop(explode(".",$file_name));

Why are higher versions so restricted?

I looked at the function prototype in the manual:

mixed array_pop ( array &$array )
bool array_walk ( array &$array , callable $funcname [, mixed $userdata = NULL ] )

& symbol specifies that the variable is passed in, which is passed by reference. Just change

to:

$file_name_arr = explode(".",$file_name);
$suffix = array_pop($file_name_arr);

.

Actually, it’s just a warning. Not a fatal error. Normal results can be obtained. For example, it is normal to get the suffix of the file name here.

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I hope this article will be helpful to everyone in PHP programming.

The above introduces the analysis of PHP variable reference and the reference passing precautions for PHP function value transfer, including the content of PHP variable reference. I hope it will be helpful to friends who are interested in PHP tutorials.