What is the use of the throw keyword in PHP?

In PHP, the throw the keyword is used to manually trigger or “throw” an exception. Exceptions are a way to handle errors or exceptional conditions in PHP code by interrupting the normal flow of execution and transferring control to an exception handler.

Syntax:

throw new Exception("Error message");

Important:

• The throw keyword is followed by the new keyword, which instantiates an exception object.
• The exception object typically contains information about the error, such as an error message or code.
• When throw is executed, PHP immediately stops executing the current code block and looks for an appropriate exception handler to handle the thrown exception.

Usage:

• Error Signaling: throw is used to signal an error or exceptional condition within the code.
• Exception Handling: Thrown exceptions are caught and handled by exception handlers, typically defined within try-catch blocks.
• Custom Error Messages: Exception objects can be customized to include specific error messages, codes, or additional data to provide context for the exception.

Example: Implementation to show the use of the throw keyword in PHP.

PHP

<?php
// Throw an exception when a division by zero occurs
function divide($dividend, $divisor)
{
    if ($divisor == 0) {
        throw new Exception("Division by zero");
    }
    return $dividend / $divisor;
}

try {
    // Attempt to perform division
    echo divide(10, 0);
} catch (Exception $e) {
    // Handle the exception
    echo "Exception caught: " . $e->getMessage();
}

?>

Output

Exception caught: Division by zero