此擴展被認為已無(wú)人維護及已消亡。然而，此擴展的源代碼還可在 PECL SVN 找到： ? https://svn.php.net/viewvc/pecl/fdf.
This extension is no longer bundled with PHP.
注意: If you run into problems configuring PHP with fdftk support, check whether the header file fdftk.h and the library libfdftk.so are at the right place. The configure script supports both the directory structure of the FDF SDK distribution and the usual DIR/include / DIR/lib layout, so you can point it either directly to the unpacked distribution directory or put the header file and the appropriate library for your platform into e.g. /usr/local/include and /usr/local/lib and configure with --with-fdftk=/usr/local.
注意: Note to Win32 Users
為了使此擴展生效， DLL 文件必須能在 Windows 系統的 PATH 指示的路徑下找到。如何操作的信息，請參見(jiàn)題為“如何在 Windows 中將 PHP 目錄加到 PATH 中”的FAQ。雖然將 DLL 文件從 PHP 文件夾復制到 Windows 系統目錄也行，但不建議這樣做。 此擴展需要下列文件在 PATH 路徑中： fdftk.dll