How to debug PHP functions?

How to debug PHP functions? Install and configure the XDebug debugger. Set up the IDE to use XDebug. Set breakpoints in your code. Start a debugging session to execute code line by line. Check variable values ​​and continue debugging to find errors and resolve problems.

How to debug PHP functions

Introduction

Debugging PHP functions is crucial , which helps you find and resolve errors in your code. This tutorial guides you through debugging PHP functions using the XDebug debugger.

Install XDebug

To install XDebug, please follow these instructions:

1. Go to [XDebug website](https:// xdebug.org/download.php) and download the version of XDebug for your version of PHP.
2. Extract the downloaded file and copy the extensions folder to your PHP extensions directory (usually /usr/lib/php/<php_version>/modules/).
3. Edit the php.ini file and uncomment the following lines:

;extension=xdebug.so

Configure XDebug

To make XDebug ready for PHP function debugging To prepare, you need to configure its settings. In the php.ini file, find the following section and modify it accordingly:

[xdebug]
xdebug.remote_enable=1
xdebug.remote_host=localhost
xdebug.remote_port=9000

Setting up the IDE

Next, you need to set up your IDE to use XDebug. See the XDebug documentation for specific instructions on different IDEs.

Practical Case

Let’s debug a simple PHP function that adds two numbers.

function addNumbers($num1, $num2) {
  return $num1 + $num2;
}

echo addNumbers(10, 20); // 输出: 30

Step 1: Set a breakpoint

Open the PHP file in the IDE and set a breakpoint, just above the return statement.

Step 2: Start a debugging session

In the IDE, start a debugging session. This will start XDebug and listen for connections from the IDE.

Step 3: Step through the function

The IDE will execute the PHP function, stepping through the code and allowing you to check the value of the variable. When execution reaches a breakpoint, the IDE will pause.

Step 4: Check Variables

In the IDE, you can check the values ​​of function parameters and local variables. This will help you determine if there is an error.

Step 5: Continue debugging

You can continue the debugging session using the options provided by the IDE, including:

• Single-step into functions
• Execute statement by statement
• View function call stack

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