## Pseudo-types and variables used in this documentation

Pseudo-types are keywords used in the PHP documentation to specify the types or values an argument can have. Please note that they are not primitives of the PHP language. So you cannot use pseudo-types as typehints in your own custom functions.

### mixed

`mixed` indicates that a parameter may accept multiple (but not necessarily all) types.

gettype() for example will accept all PHP types, while str_replace() will accept strings and arrays.

### void

`void` as a return type means that the return value is useless. `void` in a parameter list means that the function doesn't accept any parameters. As of PHP 7.1 `void` is accepted as a function return type hint.