PHP comes with hundreds of ready-made, built-in functions, making it
a very rich language. To use a function, call it by name. For example, you
can see the
print("print is a function");
The parentheses tell PHP that you’re referring to a function. Otherwise, it thinks you’re referring to a constant. You may see a warning such as this:
Notice: Use of undefined constant
fname- assumed '
followed by the text string
the assumption that you must have wanted to put a literal string in your
code. (Things are even more confusing if there is actually a constant
fname, in which case PHP uses its
print "print doesn't require parentheses";
You do have to put parentheses after any other function you call, even if it’s empty (that is, if you’re not passing any argument to the function).
Functions can take any number of arguments, including zero. For
phpinfo, as shown below,
displays lots of information about the current installation of PHP and
requires no argument. The result of calling this function can be seen in
Figure 5-1. The output of PHP’s built-in phpinfo function
phpinfo function is extremely useful for obtaining information about your current ...