Why Am I Getting the 'Fatal error: Cannot Redeclare' Error in PHP?

"Fatal error: Cannot Redeclare " - Troubleshooting PHP Function Duplication

Understanding the Error

The error "Fatal error: Cannot redeclare " indicates that a PHP function is being declared more than once within the same PHP script or within multiple included files.

Possible Causes and Solutions

• Function Declaration in Different Files: Ensure that the function is defined in only one PHP file. Search for other PHP files that may contain the same function declaration.
• Duplicate Declaration within Same File: Check for multiple instances of the function declaration within the same file. Ensure that the function is defined only once.
• Repeated Inclusion of Function File: Validate that the file containing the function definition is not being included twice in the script. Use include_once instead of include to prevent the file from being included multiple times.

Resolving the Issue

To resolve this error, follow these steps:

• Identify Duplicate Declarations: Use a code editor or search tool to locate all instances of the function declaration.
• Eliminate Duplicates: Remove any duplicate declarations from the PHP script or included files.
• Ensure Unique Function Name: Verify that the function name is unique within the scope of the script or files.
• Check for Repeated File Inclusion: If the function is defined in an included file, use include_once to prevent multiple inclusions.

Example: Applying the Solution

In the provided example, the error is likely caused by a repeated inclusion of the functions.php file. To resolve it:

include_once 'functions.php';  // Use include_once to include the file only once

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