Header files for hardware coding in c++

C++ has no standard for hardware, the same as it having no support for multithreading, input devices or even a monitor. These are all things provided externally through API. For hardware you will need to find a driver that uses the hardware or an intermediate layer like DirectInput that does the driver side for you.

C++ is platform independent, which means it has no intrinsic knowledge of the hardware it's running on. There are header files such as stdio.h, io.h, and conio.h, which I assume is what you meant by "built-in" header files.

In Windows, the hardware layer is abstracted by the functions provided by Win32 and the Platform SDK, and (at an even lower level) by the DDK. You can download these SDKs from Microsoft and examine the header files that will be installed on your system.

First thing you need to know is User Mode and Kernel Mode execution. Your program is user-mode program, and cannot directly access the hardware. To access the hardware, you program must be executing the instruction in kernel-mode. Device drives, for example run in kernel mode, and they need installation (Driver installation, heard this term?).

See Task Manager 'Show Kernel Times' - find yourself where it is!

Device drives are nothing but services (cannot be seen from services.exe, but can be enumerated using Service Functions[^].

Therefore you need to learn (study, read!), about user-mode and kernel-mode, and how they fit in with services. Start writing your own service (not device driver), and then jump to device-driver development if you can.