After phpize compiles the extension correctly, there is really nothing to load. ..

  question

Yesterday, I encountered a problem with the source code compile PHP extension under linux. I haven’t fully understood it yet. please give me some advice.

Apache mysql php has been compiled and installed, and the PHP program can also be executed. when running a PHP file, mbstring is prompted that there is no such extension.

Also use phpize configure make make install to compile and install. After looking at the installation directory of PHP, mbstring.so has indeed been correctly compiled into the PHP InstallPath \ Extensions directory. php.ini has also opened mbstring.so.
In gnome-terminal runs PHP -m, but without the extension mbstring.so, restart apache,,, through PHP phpinfo (); The extension mbstring.so is also not loaded. . . .

Where does this problem appear? Please give me some advice
System Environment: debian linux
apache 2.4.6
mysql 5.6
php 5.5.4
They are all the latest ones.

Lookphpinfo()insideConfiguration File (php.ini) PathIs it php.ini that you modified?extension_dirIs it the location of mbstring.so