Windows10下XAMPP环境安装Composer遇PDO加载错误问题求助

Hey there, let's work through these two warning messages step by step to get Composer installed smoothly:

1. Resolve "Unable to load dynamic library 'php_pdo.dll'" #

First off, here's a key point: In modern PHP versions (like the ones bundled with recent XAMPP releases), PDO is built directly into the PHP core—you don't need to load a separate php_pdo.dll extension anymore. That's why the file is missing from your ext folder, even though you uncommented the line in php.ini.

To fix this:

• Open your php.ini file (located at C:\xampp\php\php.ini)
• Search for the line that looks like extension=php_pdo.dll or extension=pdo
• Re-add the comment marker (;) at the start of that line to disable it
• Save the file and restart your XAMPP Apache and PHP services

2. Fix "Module 'openssl' already loaded" #

This warning pops up because the openssl extension is being loaded twice somewhere in your configuration. Here's how to track it down:

• Open your php.ini file and search for openssl
• You'll likely find two uncommented lines related to it—maybe one like extension=openssl and another like extension=php_openssl.dll
• Keep only one uncommented line (preferably the one without the .dll suffix, which is standard for newer PHP versions) and comment out the duplicate
• Additionally, check XAMPP's Apache configuration files (like httpd.conf or httpd-xampp.conf in C:\xampp\apache\conf) to make sure there aren't any extra lines loading the openssl module
• Save all changes and restart your XAMPP services

Verify the Fix #

After making these changes, open a command prompt and run:

php -v

Or to check loaded modules directly:

php -m

If the warnings are gone, you should be able to run the Composer installer without issues.

内容的提问来源于stack exchange，提问作者Firas-na