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Q:

How to use PHP global variable for 2 functions?

Hello everyone,

I am fairly new to PHP and I have been working on a project where I need to use a global variable across two different functions. I have been trying to figure out how to do this, but I am having some trouble.

To give you some context, I have a variable called `$globalVar` that I want to access and modify in both `functionA()` and `functionB()`. The value of `$globalVar` will be set initially in `functionA()` and then I want to use or modify the same value in `functionB()`.

I have tried using the `global` keyword to declare the variable as global in both functions, but it doesn't seem to work as expected. Here is an example of what I have attempted so far:

```
function functionA() {
global $globalVar;
$globalVar = 'Hello World';
}

function functionB() {
global $globalVar;
echo $globalVar;
}

functionA();
functionB();
```

In this example, I expect the output of `functionB()` to be "Hello World", but it just prints an empty string.

I have also tried using the `$GLOBALS` array as follows:

```
function functionA() {
$GLOBALS['globalVar'] = 'Hello World';
}

function functionB() {
echo $GLOBALS['globalVar'];
}

functionA();
functionB();
```

But this also doesn't seem to work as expected.

I would really appreciate it if someone could guide me on how to correctly use a global variable across multiple functions in PHP. Is there something I am missing or any other approach I should be using?

Thank you in advance for your help!

All Replies

pattie14

User 1 here,

I have faced a similar issue before, where I needed to use a global variable across multiple functions in PHP. I found that using the `global` keyword should work, but there might be some other issue in your code.

One thing you need to ensure is that you are calling `functionB()` after `functionA()`, as the value of the global variable is set in `functionA()`. Also, double-check that you have included the `global $globalVar` declaration within each function.

Here's an example of how I have used a global variable successfully in the past:

php
$globalVar = ''; // Declare the global variable outside the functions

function functionA() {
global $globalVar;
$globalVar = 'Hello World';
}

function functionB() {
global $globalVar;
echo $globalVar;
}

functionA();
functionB();


In this scenario, if you execute this code, `functionB()` will output "Hello World" as expected.

If this approach doesn't work for you, there might be some other factor affecting the behavior. Make sure there are no syntax errors or typos in your code, and verify that the variable is not being reassigned or modified elsewhere in your program.

I hope this helps you resolve your issue. If you have any further questions or need more assistance, feel free to ask!

cormier.justyn

User 2 here,

I had faced a similar challenge in using a global variable across multiple functions in PHP, and I found an alternative approach that worked for me.

Instead of relying on the `global` keyword, you can consider passing the variable as an argument to each function. This allows you to maintain better control over the variable's scope.

Here's an example of how you can modify your code using this approach:

php
function functionA(&$globalVar) {
$globalVar = 'Hello World';
}

function functionB($globalVar) {
echo $globalVar;
}

$globalVar = ''; // Declare the global variable outside the functions
functionA($globalVar);
functionB($globalVar);


Using the `&` symbol before the variable name in the function declaration allows you to pass it by reference. This means any changes made to `$globalVar` within `functionA()` will be reflected in `functionB()`.

By adopting this method, you eliminate the need to rely on the `global` keyword, making your code more modular and manageable. Additionally, it ensures that the variable is explicitly passed between functions, making it easier to track its usage.

Give this approach a try, and see if it works for your specific use case. If you have any further questions or encounter any difficulties, please let me know. I'm here to help!

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