Title: (Global) variable issue
Last modified: August 19, 2016
---
# (Global) variable issue
* [thomasgericke](https://wordpress.org/support/users/thomasgericke/)
* (@thomasgericke)
* [16 years, 10 months ago](https://wordpress.org/support/topic/global-variable-issue/)
* I have an issue concerning (global?) variables. Some pseudo code:
* ```
function my_plugin_install() {
// glad, we have nothing to do here...
}
add_action ('my_plugin/my_plugin.php', 'my_plugin_install');
global $my_var;
$my_var = "";
function my_function() {
global $my_var;
$my_var = "true";
return $my_var;
}
add_filter ('some_foreign_call_from_another_plugin', 'my_function');
function write2header() {
global $my_var;
echo "Within our header: " . $my_var;
}
add_action ('admin_head', 'write2header');
```
* What do I want to do?
* My plugin is called by **some_foreign_call_from_another_plugin**‘s filter hook
and I immediately call **my_function**. That works well. Within that function,
I set the variable **$my_var** to “true”. That variable is defined as global
earlier.
* Later in my plugin, I want to insert some code into the part of the output.
And I want to use **$my_var** there.
* But that’s the one thing, that doesn’t work. Within the header, it says: “Within
our header: ” – but nothing more. No output of **$my_var**.
* Why? What am I doing wrong?
* Do I have to define my global variable later? Earlier? Where?
* Should I use **$GLOBALS[“my_var”]**? I already tried a little bit with that –
didn’t work either. 🙁
* Thomas
Viewing 2 replies - 1 through 2 (of 2 total)
* Thread Starter [thomasgericke](https://wordpress.org/support/users/thomasgericke/)
* (@thomasgericke)
* [16 years, 10 months ago](https://wordpress.org/support/topic/global-variable-issue/#post-1166062)
* BTW: this one totally works in a plain PHP file (without WordPress):
* ```
Hello World!
";
function my_function() {
global $my_var;
$my_var = "true";
return $my_var;
}
echo "After 2st function: " . my_function() . "
";
function my_2nd_function() {
global $my_var;
echo "In 2nd function: " . $my_var . "
";
}
my_2nd_function();
?>
```
* When calling the PHP file in a browser, output is:
* **Hello World!
Before 1st function: After 2st function: true In 2nd function:
true
* So, it must be a WordPress issue. Can someone help, please?
* Thomas
* [andykassabian](https://wordpress.org/support/users/andykassabian/)
* (@andykassabian)
* [16 years, 6 months ago](https://wordpress.org/support/topic/global-variable-issue/#post-1166227)
* I’ve got exactly the same problem, anyone got a solution?
Viewing 2 replies - 1 through 2 (of 2 total)
The topic ‘(Global) variable issue’ is closed to new replies.
## Tags
* [global variable](https://wordpress.org/support/topic-tag/global-variable/)
* In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
* 2 replies
* 2 participants
* Last reply from: [andykassabian](https://wordpress.org/support/users/andykassabian/)
* Last activity: [16 years, 6 months ago](https://wordpress.org/support/topic/global-variable-issue/#post-1166227)
* Status: not resolved
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