Create directories using Boost

Boost::filesystem provides two methods to check if directories exist and create directories if not.

#include <boost/filesystem.hpp>
 
boost::filesystem::path filePath( "/a/b/c" );
 if( !boost::filesystem::exists( filePath ) &&
     !boost::filesystem::create_directories( filePath ) ) {
    ...    
 }

C++ standard didn’t provide them until C++17.