Unable to get variables from different files

Question

Im trying to get data from my database and echo it with a variable, but I have a problem with that. When I try to get my variables from different files it shows me this error:

Undefined variable: con in.

Here some codes:

Code from functions.php:

include "authentication.php";

function GetData() {
$id = session_id();
$result3 = mysqli_query($con,"SELECT * FROM accounts where id='$id'");
while($row3 = mysqli_fetch_array($result3));
{ 
$email=$row3['email'];
$fullname=$row3['fullname'];
$usualname=$row3['usualname'];
$lastname=$row3['lastname'];
}
}

Code from authentication.php:

$DATABASE_HOST = 'localhost';
$DATABASE_USER = '***';
$DATABASE_PASS = '***';
$DATABASE_NAME = '***';

$con = mysqli_connect($DATABASE_HOST, $DATABASE_USER, $DATABASE_PASS, $DATABASE_NAME);
if ( mysqli_connect_errno() ) {

    die ('Failed to connect to MySQL: ' . mysqli_connect_error());
}

This also happens when I try to get variables from other files.. Here you get some screenshots of the error from different files and different variables:

Both files are in the same directory called PHPscripts:

Where is the location of `authentication.php`? Is that file included properly? — Talk2Nit, Aug 03 '19 at 13:52
Possible duplicate of [Reference: What is variable scope, which variables are accessible from where and what are "undefined variable" errors?](https://stackoverflow.com/questions/16959576/reference-what-is-variable-scope-which-variables-are-accessible-from-where-and) — Progman, Aug 03 '19 at 18:36

Oloff Biermann · Accepted Answer · 2019-08-03T14:17:52.253

This looks like a problem of scoping.

Remember that in PHP, variables in the global scope cannot be accessed from a function. You must explicitly do something like global $con; inside the function GetData() before you try to access $con.

From a system design point of view this isn't the best approach. It will make it hard to keep track of your variables. You won't know who (which part of your script) is accessing that global and you won't know how it is being modified or in what order. This can lead to some bugs that are very difficult to identify.

score 0 · Answer 2 · answered Aug 03 '19 at 14:04

0

require_once dirname(__FILE__) . auth.php;

Require_once or require with Unix full path works like a charm. Replace include stroke in your code.

answered Aug 03 '19 at 14:04

Vladimir

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Unable to get variables from different files

2 Answers2