Accessing global variables in PHP function

Question

I'm new to php and I can't understand why is it that the variable "cons" isn't recognized by the the compiler when used inside the function "func", in the following code:

$cons = 1;

function plusCons($num) {
   return $num + $cons;
}

is it impossible to use global variables inside of a function's scope?

declare it global $cons; inside function. See: php.net/manual/en/language.variables.scope.php — Sergiy T.
– Sergiy T., Commented Dec 13, 2012 at 12:51
You can, but it generally should be avoided. You should just pass the variable in as a parameter and then update it when the function returns, or use a class. — deed02392
– deed02392, Commented Dec 13, 2012 at 12:56

user21926 · Accepted Answer · 2012-12-13 12:52:57Z

3

In order to access global variables within a PHP function, you need to use the global keyword to import the variable:

$cons = 1;

function plusCons($num) {
   global $cons;

   return $num + $cons;
}

answered Dec 13, 2012 at 12:52

user21926

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2 Comments

Yoshi Over a year ago

this will not work in a lot of contexts, e.g. assiging a closure to a variable inside a class method. Use use(...).

user21926 Over a year ago

Right. Fortunately that isn't what the OP was inquiring about.

bluish · Accepted Answer · 2012-12-13 13:18:45Z

0

This also will work for you:

$cons = 1;

function plusCons($num ,$cons) {
  return $num + $cons;
}

echo plusCons(2 , $cons); // this will output 3

edited Dec 13, 2012 at 13:18

bluish

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answered Dec 13, 2012 at 13:00

echo_Me

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