CODEWITHSUNDEEP
phpfunctionvariablesglobal
alex2005
alex2005

Reputation: 31

global variables from one function to another

Lets say I have this:

function myFunc()
{
    global $distinct_variable;

    die ($distinct_variable);
}

function anotherFunc()
{
    $distinct_variable = 'Hello World';

    myFunc();
}

anotherFunc();

For anotherFunc() to correctly show 'Hello World', it must be written like this

{
    global $distinct_variable;

    $distinct_variable = 'Hello World';

    myFunc();
}

Now it will show the message, but why must I global $distinct_variable; in anotherFunc() since it is a global in myFunc() which is within anotherFunc()

Yes, I know that variables inside functions won't go outside of them, but I was thinking it should have worked...

Could someone explain why isn't it working? Thanks.

Thank you for your answers, I get it now :)

Upvotes: 0

Views: 718

Answers (3)

DaveRandom
DaveRandom

Reputation: 88647

A global variable is exactly that - it exists in the GLOBAL scope ONLY.

Everything in PHP (except superglobals) exist in only one scope - be that the global scope, or the scope of a function/method. Scope does not cascade - so just because you have a variable in an "outer" function does not make it available to an "inner" function.

Similarly, global fetches the variables defined in the GLOBAL scope only (the top-most scope), not simply "the scope above this one, from which I was called". This is what you tried to do, but it absolutely will not work. This level of finer-grained control is what function arguments/return values are for.

Upvotes: 3

Marc B
Marc B

Reputation: 360632

Doing global $somevar; echo $somevar boils down to echo $GLOBALS['somevar'];. That $GLOBALS superglobal does not include variables that were defined inside a function: only truly 'global' vars, which exist at the top level of the script.

Upvotes: 1

Hammerite
Hammerite

Reputation: 22340

Each function has its own symbol table. There is also a global symbol table. Just because one function is being called from within another doesn't mean that the variables declared global in one are global in the other, or inherited from the other. They still refer to the variable in the "local" symbol table by default.

Upvotes: 2

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