What are the potential pitfalls of not using global variables correctly in PHP?

When global variables are not used correctly in PHP, it can lead to issues such as variable scope conflicts and difficulties in tracking variable values throughout the code. To avoid these pitfalls, it is important to use global variables sparingly and only when necessary, ensuring that they are properly declared and accessed within functions. 

// Incorrect usage of global variable
$globalVar = 10;

function incrementGlobalVar() {
    $globalVar++; // This will cause an error as $globalVar is not properly declared as global
}

incrementGlobalVar();

// Correct usage of global variable
$globalVar = 10;

function incrementGlobalVar() {
    global $globalVar;
    $globalVar++;
}

incrementGlobalVar();
echo $globalVar; // Output: 11

Keywords

scope variable global namespace security

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