Error .

DirectX.obj : error LNK2019: unresolved external symbol "void * __cdecl DetourCreate(unsigned char *,unsigned char const *,int)" (?DetourCreate@@YAPAXPAEPBEH@Z) referenced in function "public: void __thiscall cDirectx::Hook(void)" (?Hook@cDirectx@@QAEXXZ)
1>C:\Documents and Settings\***\My Documents\Visual Studio 2008\Projects\Project1\Combined Base v2\CaBase\Release\CaBase.dll : fatal error LNK1120: 1 unresolved externals

#ifndef _DETOURS_H
#define _DETOURS_H

extern "C" int  __cdecl mlde32(void *codeptr);

int   DetourLen(BYTE *src, int minlen);
void *DetourCreate(BYTE *src, const BYTE *dst, const int minlen=0);
void  DetourRemove(BYTE *src, BYTE *restore, const int len=0);

#endif

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <stdlib.h>
#include "detours.h"


int DetourASMlen(BYTE *src, int minlen)			// find out asm instruction length
{
	int i,len;

	for (len=0; len<minlen; len+=i) {
		i=mlde32((void *)src);
		if (i<=0) return 0;
		src+=i;
	}
	return len;
}

void *DetourCreate(BYTE *src, const BYTE *dst, int minlen)
{
	BYTE	*jmp, *org;
	DWORD	dwBack;
	int		len;

	len=DetourASMlen(src,(minlen<6)?6:minlen);
	if (len==0 && minlen>=6)  len=minlen;
	if (len==0) return 0;

	org=jmp = (BYTE*)malloc(len+5+1);		// room for nobytes + jmplen + size byte
    jmp[0]=len;								// save length in first byte
    jmp++;

	VirtualProtect(src, len, PAGE_EXECUTE_READWRITE, &dwBack);
	memcpy(jmp, src, len);	
	jmp += len;
	jmp[0] = 0xE9;
	*(DWORD*)(jmp+1) = (DWORD)(src+len - jmp) - 5;

	src[0] = 0x68;							// different hook,  push address   ret
	*(DWORD*)(src+1) = (DWORD)(dst);
	src[5] = 0xc3;
	for (int i=6; i<len; i++)  src[i] = 0x90;
	VirtualProtect(src, len, dwBack, &dwBack);

	return &org[1];							// return entry point, byte 0 = length
}

// restore == return value of DetourCreate
void DetourRemove(BYTE *src, BYTE *restore, int len)
{
	DWORD dwBack;

	len=*(BYTE *)(restore-1);		// ignore len parameter, only for backward competability

	VirtualProtect(src, len, PAGE_EXECUTE_READWRITE, &dwBack);
	memcpy(src, restore, len);
	restore[0] = 0xE9;

	*(DWORD*)(restore+1) = (DWORD)(src - restore) - 5;
	VirtualProtect(src, len, dwBack, &dwBack);
}