Unset () function no longer has the return value due to the red warning?

I don't know why I can't show it properly.
It's not the same as PHP from beginner to Proficient (3rd edition) 34 page run result 3.5.

What is this about?

Reply content:

I don't know why I can't show it properly.
It's not the same as PHP from beginner to Proficient (3rd edition) 34 page run result 3.5.

What is this about?

Please po main self Baidu error_reporting , php notice错误 , and php 错误等级详解 other key words

Baidu next PHP unset () function

That's just the warning,php variable does not declare can be used (and C is not the same)

Code to start writing: error_reporting (0);

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