How install PDFLIB and see in phpinfo

I'm trying to make PDFlib to work on wamp. I've downloaded http://www.pdflib.com/download/pdflib-family/pdflib-8/ and followed the installation guide ..

I took the libpdf_php.dll and i copied it in C:\wamp\bin\php\php5.4.12\ext (of course i take php-540_VS9 of libpdf?  ) i have php version 5.4.12

than i added in php.ini : extension = libpdf_php.dll

my pc and my operating system to windows 7 x64, I can't make it work I do not get this section of pdflib in phpinfo() :

Any ideas ?

Solution

first of all, it's not recommended to download the old and outdated PDFlib 8 for starting
then its important, that you copy the correct DLL depending to your used PHP version to your extension_dir. You find the correct extension_dir in your phpinfo() output.
then you have to add the PDFlib DSO to the correct php.ini. You find the path to the correct php.ini in the phpinfo() output.
also when you are on a 64-bit Windows systems, it't important that you use a 32-bit PHP stack when using the old PHP 5.4. (PHP versions before 7.0 do support 64-bit in on Windows just in experimental use. PDFlib don't provide precomiled DSO for such combinations

In addition, I would recommend, to check the error/webserver log file, possible hints why the extension loading failed.