title: C : How to link all o file into one file
body: <p>I try to integrate a C library into my project. The custom makefile of this project try to compile all source files, each file into one object file (<code>*.o</code>). </p>
  
  <p>I need to link all of those <code>*.o</code> files into one file, for example <code>so</code> file, for easily to use it. Do I need this ? And if yes, how can I link all of <code>*.o</code> files into one library file. Which lines I will add to Makefile ?</p>
  
  <p>(Notes that, this C library include many sub-directory, and a big makefile will go into all sub directories, and use Makefile in each directory to run it)</p>
  
  <p>Thanks :)</p>