Question

i am relatively new to php and i’ve encountered a very strange problem.
let me just give an example of a really simple code

$test = 'test';

function test(){
    echo $test;
}

test();

in the above example, it used to work just perfectly fine, returning ‘test’ as a result of calling the test() function. however, just today it started to return error saying the variable $test is undefined. i am 100 percent sure it worked just fine before. is this some update in php? or am i doing something wrong here? i am using wamp and testing this on my localhost. thanks!

Answer 1

This is expected behaviour, it’s called “variable scope”

read this: http://php.net/manual/en/language.variables.scope.php

One of the ‘pitfalls’ is:

You may notice that this is a little bit different from the C language
in that global variables in C are automatically available to functions
unless specifically overridden by a local definition. This can cause
some problems in that people may inadvertently change a global
variable. In PHP global variables must be declared global inside a
function if they are going to be used in that function.