2--php defined function ill defined be defined by already defined

* * Copyright (c) 2016, School of Computer and Control engineering, Yantai University * All rights reserved. * File name: Text.cpp * Author: Changxuan * Public Number: Worldhello * Completion Date: May 18, 2016 * version number: V1.0 * Problem Description: PHP * Program Input: NO * program output: no * *
 
 

The defined () function helps us to determine whether a constant has been defined and its syntax is:

bool Defined (String Constants_name

Returns a Boolean type True if it exists, otherwise returns a Boolean type of false; (Note: bool means the return value type of the function is a Boolean type)

The above describes the 2--php defined function, including the defined aspects of the content, I hope that the PHP tutorial interested in a friend helpful.

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