The callback function used in SetWindowsHookEx is only called once - c++

Question

I'm in the process of writing a dll-injected global keyboard hook but have run into a problem which I can't seem to get past. So far I have one program which is in charge of loading the dll and calling the SetWindowsHookEx, and ofcourse the dll to be injected.
The DLL looks like this:
#include "stdafx.h"
#include <stdio.h>
#include <windows.h>
#include <string>
using namespace std;
INT APIENTRY DllMain(HMODULE hDLL, DWORD Reason, LPVOID Reserved) {
switch(Reason) {
case DLL_PROCESS_ATTACH:
//fprintf(file, "DLL attach function called.\n");
break;
case DLL_PROCESS_DETACH:
//fprintf(file, "DLL detach function called.\n");
break;
case DLL_THREAD_ATTACH:
//fprintf(file, "DLL thread attach function called.\n");
break;
case DLL_THREAD_DETACH:
//fprintf(file, "DLL thread detach function called.\n");
break;
}
return TRUE;
}
extern "C" __declspec(dllexport) int meconnect(int code, WPARAM wParam, LPARAM lParam) {
if (code == HC_ACTION)
{
FILE *file;
string c;
c += (char)wParam;
fopen_s(&file, "c:\\temp2.txt", "a+");
fprintf(file, c.c_str());
fclose(file);
}
return(CallNextHookEx(NULL, code, wParam, lParam));
}
The main program looks like this:
#include <Windows.h>
#include <iostream>
#include <SDKDDKVer.h>
using namespace std;
void CheckForExit(HHOOK handle);
int main()
{
/*
* Load library in which we'll be hooking our functions.
*/
HMODULE dll = LoadLibrary(L"dllinject.dll");
if (dll == NULL) {
printf("The DLL could not be found.n");
//getchar();
return -1;
}
/*
* Get the address of the function inside the DLL.
*/
HOOKPROC addr = (HOOKPROC)GetProcAddress(dll, "meconnect");
if (addr == NULL) {
printf("The function was not found.n");
//getchar();
return -1;
}
DWORD id = GetCurrentThreadId();
HHOOK handle = SetWindowsHookEx(WH_KEYBOARD, addr, dll, 0);
if (handle == NULL) {
printf("The KEYBOARD could not be hooked.n");
}
/*
* Unhook the function.
*/
system("pause");
UnhookWindowsHookEx(handle);
return 0;
}