How can PHP extensions like fdftk be properly configured and integrated to avoid errors like "Call to undefined function fdf_open()"?

To properly configure and integrate PHP extensions like fdftk, you need to ensure that the extension is enabled in your PHP configuration file (php.ini) by uncommenting the extension line. Additionally, you may need to install the necessary dependencies for the extension to work correctly. Once these steps are completed, you should no longer encounter errors like "Call to undefined function fdf_open()".

// Ensure the fdftk extension is enabled in your php.ini file
// extension=fdftk.so

// Make sure the necessary dependencies for fdftk are installed
// For example, on Ubuntu you can install the necessary package with: sudo apt-get install libfdftk1

// Now you can use functions like fdf_open() without encountering errors