How to use class CConsole?

[zsdz]

I can write a simple prog to write "Hello World":

main.cpp

#include "kernel.h"
#include <circle/startup.h>

int main (void)
{
	// cannot return here because some destructors used in CKernel are not implemented

	CKernel Kernel;
	if (!Kernel.Initialize ())
	{
		halt ();
		return EXIT_HALT;
	}
	
	TShutdownMode ShutdownMode = Kernel.Run ();

	switch (ShutdownMode)
	{
	case ShutdownReboot:
		reboot ();
		return EXIT_REBOOT;

	case ShutdownHalt:
	default:
		halt ();
		return EXIT_HALT;
	}
}

kernel.h:

#ifndef _kernel_h
#define _kernel_h

#include <circle/koptions.h>
#include <circle/devicenameservice.h>
#include <circle/screen.h>
#include <circle/types.h>

enum TShutdownMode
{
	ShutdownNone,
	ShutdownHalt,
	ShutdownReboot
};

class CKernel
{
public:
	CKernel (void);
	~CKernel (void);

	boolean Initialize (void);

	TShutdownMode Run (void);

private:
	// do not change this order
	CKernelOptions		m_Options;
	CDeviceNameService	m_DeviceNameService;
	CScreenDevice		m_Screen;
};

#endif

kernel.cpp:

#include "kernel.h"
#include <circle/string.h>
#include <circle/debug.h>

CKernel::CKernel (void)
:	m_Screen (m_Options.GetWidth (), m_Options.GetHeight ())
{
}

CKernel::~CKernel (void)
{
}

boolean CKernel::Initialize (void)
{
	return m_Screen.Initialize ();
}

TShutdownMode CKernel::Run (void)
{
	
	CString Message("Hello world");
		
	m_Screen.Write ((const char *) Message, Message.GetLength ());
	
	return ShutdownHalt;
}

it works fine!
I want to use class CConsole to do the same thing,the main.cpp is the same,the change is:
kernel.h:
#include <circle/input/console.h>

private:
	// do not change this order
	CKernelOptions		m_Options;
	CDeviceNameService	m_DeviceNameService;
	CConsole m_pConsole;

kernel.cpp:

CKernel::CKernel (void):m_pConsole(0,FALSE)
{
}

TShutdownMode CKernel::Run (void)
{
	
	CString Message("Hello world");
	
	m_pConsole.Write(Message,Message.GetLength());
	
	return ShutdownHalt;
}

make,but got error:
kernel.cpp:25:(.text+0x30): undefined reference to `CConsole::CConsole(CDevice*, bool)'

the doc (https://circle-rpi.readthedocs.io/en/49.0/devices/character-devices.html#cconsole) said:

CConsole::CConsole(CDevice *pAlternateDevice = 0, boolean bPlugAndPlay = FALSE)
Creates an instance of this class. pAlternateDevice is an alternate device to be used, if the USB keyboard is not attached (default none). bPlugAndPlay must be set to TRUE to enable USB plug-and-play support for the console. This constructor is mandatory for USB plug-and-play operation.

I use usbkeyboard,so the first parameter is 0,the keyboard is already connect to the rpi4b,so the second parameter is false,so the line I write:

CKernel::CKernel (void):m_pConsole(0,FALSE)
{
}

should be right.Why I got the make error?How to fix it?Thanks!

[rsta2]

Attached you'll find the simplest version of a program, which uses the CConsole class.

The library lib/input/libinput.a must be listed in LIBS in the Makefile to suppress the make error.

console-simple.zip