Sams Teach Yourself PHP in 24 Hours, Third Edition

Calling Functions

Functions come in two flavors—those built in to the language and those you define yourself. PHP has hundreds of built-in functions. One of the earliest scripts in this book used the gettype() function:

gettype( $testing );

We called gettype() and passed it the $testing variable. The function then went about the business of testing the variable. A function call consists of the function name—gettype in this case—followed by parentheses. If you want to pass information to the function, you place it between these parentheses. A piece of information passed to a function in this way is called an argument. Some functions require that more than one argument be passed to them. Arguments in these cases must be separated by commas, ...