PHP Tutorials - Herong's Tutorial Examples - Version 4.20, by Dr. Herong Yang
Function Call Operations
This section describes the function call operation, which triggers the execution of the called function with arguments provided on the call.
Calling a function in PHP is simple. All you have to do is to just use the function name with an argument list in any expression:
... function_name(argument_1, argument_2, ...) ...
When the execution reaches this function call operation, it will:
Here is a simple example script showing us how to use function call operations:
<?php # FunctionCallOperations.php #- Copyright (c) 2003-2019, HerongYang.com, All Rights Reserved. # # Defining a function that returns a value function f2c($fahrenheit) { $celsius = ($fahrenheit - 32.0 ) / 1.8; return $celsius; } # Defining a function that returns NULL function showAnyFooter($author) { print(" Copyright: $author\n"); print(" Last Modified: 2015\n"); } print("\n Function call as a standalone expression:\n"); showAnyFooter("Herong Yang"); print("\n Function call as an operand of another operation:\n"); if (f2c(20.0)<0.0) print(" It's cold here!\n"); print("\n Function call as an argument of another call:\n"); print(" How is the temperature? "); print(f2c(110.0)); ?>
If you run this sample script, you should get:
C:\herong> \php\php FunctionCallOperations.php Function call as a standalone expression: Copyright: Herong Yang Last Modified: 2019 Function call as an operand of another operation: It's cold here! Function call as an argument of another call: How is the temperature? 43.3333333333
Last update: 2019.
Table of Contents
Introduction and Installation of PHP 7.3
PHP Data Types and Data Literals
Variables, References, and Constants
Expressions, Operations and Type Conversions
Conditional Statements - "if" and "switch"
Loop Statements - "while", "for", and "do ... while"
►Function Declaration, Arguments, and Return Values
"function" Statements - Defining Functions
Passing Arguments to Functions
Example of Passing Arguments by Values
Using Pass-by-Value Arguments for References
Example of Passing Arguments by References
Variable-Length Argument Lists
Providing Default Values to Argument Variables
Returning Values from Functions
Returning References from Functions
Introduction of Class and Object
Integrating PHP with Apache Web Server
Retrieving Information from HTTP Requests
Creating and Managing Sessions in PHP Scripts
Sending and Receiving Cookies in PHP Scripts
Controlling HTTP Response Header Lines in PHP Scripts
MySQL Server Connection and Access Functions
Functions to Manage Directories, Files and Images
SOAP Extension Function and Calling Web Services
SOAP Server Functions and Examples
Localization Overview of Web Applications
Using Non-ASCII Characters in HTML Documents
Using Non-ASCII Characters as PHP Script String Literals
Receiving Non-ASCII Characters from Input Forms
"mbstring" Extension and Non-ASCII Encoding Management
Managing Non-ASCII Character Strings with MySQL Servers