Where are php's extensions .so files located?

Question

I opened some some ini files like mysqli.ini , mysql.ini , pdo_mysql.ini. Inside those files there is an .so extension added for those files. I want to know where these .so files are stored.

Inside mysqli.ini file

; configuration for php MySQL module
; priority=20
extension=mysqli.so

Inside mysql.ini file

; configuration for php MySQL module
; priority=20
extension=mysql.so

Inside pdo_mysql.ini file

; configuration for php MySQL module
; priority=20
extension=pdo_mysql.so

Solution

The .so files should be located inside your php extension directory.

You can use phpinfo() function to find the location of your php extension directory or you can use php -i from the command line.

Example

root@73fa7795de48:/# php -i | grep extension_dir
extension_dir => /usr/lib/php/20160303 => /usr/lib/php/20160303