Error handling in PHP functions

The steps to implement error handling in PHP are as follows: use set_error_handler() to connect an error handler to the function; define the error handler and specify the error type to be captured; trigger the error message through trigger_error(); capture in the error handler and handle errors, such as printing error information; you can customize the error type and specify the custom errors to be captured; use restore_error_handler() to restore to the default error handling behavior.

Error Handling in PHP Functions: A Practical Guide

In PHP, error handling is crucial to ensure that the program runs stably and reliably. By connecting an error handler to a function, we can catch and handle any errors that may occur in function calls.

Syntax

set_error_handler(callable $error_handler, int $error_types = E_ALL | E_STRICT);

• $error_handler: A callable object used to handle errors.
• $error_types (optional): Bitmask constant for errors to catch.

Practical case

Let us write a function to calculate the quotient of two numbers and use error handling to handle the case where the divisor is 0:

function divide($numerator, $denominator)
{
    if ($denominator == 0) {
        trigger_error("Cannot divide by zero", E_USER_ERROR);
    }

    return $numerator / $denominator;
}

We Next set up an error handler to catch errors in this function:

set_error_handler(function(int $errno, string $errstr) {
    if ($errno === E_USER_ERROR) {
        echo "Error: $errstr\n";
    }
});

$result = divide(10, 2); // 输出: 5
$result = divide(10, 0); // 输出: Error: Cannot divide by zero

Custom Error Type

We can also create a custom error type using trigger_error(), And specify custom errors to be captured via $error_types:

function trigger_custom_error()
{
    trigger_error("Custom error", E_USER_NOTICE); // 创建自定义错误
}

set_error_handler(function(int $errno, string $errstr) {
    if ($errno === E_USER_NOTICE) {
        echo "Custom error occurred: $errstr\n";
    }
});

trigger_custom_error(); // 输出: Custom error occurred: Custom error

Restore error handling

To revert to the default error handling behavior, you can use restore_error_handler() Function:

set_error_handler(function() {}); // 设置自定义错误处理程序
restore_error_handler(); // 恢复到默认错误处理

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