src folder in sketch structure and include library from subfolder

Question

My Arduino/PlatformIO libraries folder

libraries
└── cleaner_robot
    └── TB6612_Dual
        ├── tb6612_dual.h
        └── tb6612_dual.cpp

I used this code to innclude it:

#include <TB6612_Dual/tb6612_dual.h>

But the compilation has errors like "undefinded variables, undefinded reference,...etc"

This is my sketch folder

Cleaner_Robot
└── src
    └── TB6612_Dual
        ├── tb6612_dual.cpp
        └── tb6612_dual.h

If i use this code, all is ok

#include "src/libs/TB6612_Dual/tb6612_dual.h"

So the question is how to include if header file is in a sub folder of a folder in libraries folder of Arduino/PlatformIO ?, i has searched for many things, but cant help. I also read about src folder allowed in Arduino, but where can find an official announcement/manual for this structure ?, cant find much about this

Thanks  :)  

Answer 1

I could include header files in subfolder after including root header file.

#include <TB6612_Dual.h>
#include <TB6612_Dual/tb6612_dual.h>

TB6612_Dual
└── src
    ├── TB6612_Dual.h << Add this empty file.
    └── TB6612_Dual
        ├── tb6612_dual.cpp
        └── tb6612_dual.h

Examples:

• utils_asukiaaa/examples/string/string.ino
• utils_asukiaaa/src/utils_asukiaaa/string.h
• utils_asukiaaa/src/utils_asukiaaa/string.cpp
• utils_asukiaaa/src/utils_asukiaaa.h