Sendchar error LPC2148

Hello,

When I try to compile my program I get the following error:

'project.axf: Error L6218E: Undefined symbol sendchar (referred from retarget.o).'

I've tried to solve this error for quite a while now, but it doesn't work out. I've read other forum threads and I've searched through the net, but I can't find a satisfying answer.

Some background info:
I'm trying to get the UART0 working on the LPC2148.
I use Keil uVision3 and I use the Philips LPC2000 Flash Utility V2.2.3 to upload the .hex file to the microcontroller.

I'm new with the UART and I find it quite difficult to work with.

This is the Retarget.c:

#include <stdio.h>
#include <rt_misc.h>

#pragma import(__use_no_semihosting_swi)

extern int sendchar(int ch);

struct __FILE (int handle;);
FILE __stdout;

int fputc(int ch, FILE *f) {
return (sendchar(ch));
}

int ferror(FILE*f) {
return EOF;
}

void _ttywrch(int ch) {
sendchar(ch);
}

void _sys_exit (int return_code) {
label: goto label;
}

I've tried several codes and everytime I get the same error. I've also tried the example code from 'The Insiders Guide To The Philips ARM7-Based Microcontrollers' for initializing the UART, which is:

#include "lpc214x.h"

void init_serial (void)
{
PINSEL0 = 0x00050000;
U1LCR = 0x00000083;
U1DLL = 0x000000C2;
U1LCR = 0x00000003;
}

int putchar (int ch)
{
if (ch == '\n') {
while (!(U1LSR & 0x20));
U1THR = CR
}
while (!(U1LSR & 0x20));
return (U1THR = ch);
}

int getchar (void)
{
while (!(U1LSR & 0x01));
return (U1RBR);
}

If I try to compile that, I get the error:

schiet.axf: Error: L6218E: Undefined symbol main (referred from kernel.o).

For my school project I need to get the LPC2148 communicating with a scoreboard. All that I have to get the LPC2148 to do is sending a code to the scoreboard to raise the score with '1' and I need to retrieve it's current score. But I have no ideas left how to get this working.

I hope that I've made my problem clear enough!

Kind regards!