Pseudo-Type in PHP

1.mixed

Mixed indicates that a parameter can accept many different (but not necessarily all) types.

For example, GetType () can accept all PHP types.
2.number
Number indicates that a parameter can be an integer or float.

3.callback

Callable usage after PHP 5.4
4.void

void as the return type means that the return value of the function is useless.

void as a parameter list means that the function does not accept any arguments.

5. "..."

In the function prototype, $ ... The meaning of the expression and so on.

This variable name is used when a function can accept any parameter.

The above introduces the pseudo-type in PHP, including the content of the aspects, I hope that the PHP tutorial interested in a friend helpful.

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