Have you guys ever read this article:

http://www.possibility.com/Cpp/CppCo...d.html#classes

What are "SYSTEM INCLUDES,PROJECT INCLUDES, LOCAL INCLUDES,FORWARD REFERENCES"? Which are introduced in " Include Statement Documentation" part

System includes are those provided by the system, typically by the C++ language such as iostream angle brackets are used:

#include <iostream>

Project includes are those which are written for the project, double quotes are used:

#include "myClass.h"

Forward references are where the compilers is told that a variable will be used but it has not been defined yet.

class myClass;
class myOtherClass
{
// uses myClass
};

class myClass
{
// possibly uses myOtherClass
};

Thanks a lot! But what is local include?

I'm not familiar with the term local include. I would guess that the way the author uses it is that project includes are for project wide data - such as globals whilst local includes are includes for more local definitions such as the class.

I don't believe that is standard terminology so there are possibly different ways to interpret it. Another order could be:

System Includes
3rd Party Libraries
Project Libraries
Project includes

a local include would be a header file that should be accessible only by the lib that it resides in. consider a structure like

/
-libA
+ libA.h
+ libA_local.h
+ libA.c
+ libA_utils.c
-libB
+ libB.h
+ libB_local.h
+ libB.c
+ libB_utils.c


libA will have functions/vars in libA.h that should be visible to libB, while libA_local.h will have functions/vars that for one reason or another will be visible only within the libA library. this is then enforced by having your makefile copy the public headers to a project include file that everything is included from for the build. this prevents other libs from just using an absolute path to the *_local header.