PHP 7 Quick Scripting Reference, Second Edition

© Mikael Olsson 2016

Mikael Olsson, PHP 7 Quick Scripting Reference, 10.1007/978-1-4842-1922-5_18

18. Type Declarations

Mikael Olsson¹ 

(1)Hammarland, Finland

Type declarations allow a function to declare the expected types of their parameters and return value. This permits the PHP engine to enforce that the specified types are used.

Argument Type Declarations

Early versions of PHP relied exclusively on proper documentation of functions for developers to know what arguments a function accepts. To allow for functions that are more robust, PHP 5 began to introduce argument type declarations, permitting the type of a function parameter to be specified. Valid types for type declarations are shown in Table 18-1, along with the PHP version in which these ...