C / C++ / MFC

#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <detours.h>
#include <string.h>

static int (WINAPI* winMessageBox)(
    HWND hWnd,
    LPCTSTR lpText,
    LPCTSTR lpCaption,
    UINT uType) = MessageBox;

int WINAPI __stdcall hookedMessageBox(      
	HWND hWnd,
	LPCTSTR lpText,
	LPCTSTR lpCaption,
	UINT uType) {
	return winMessageBox(hWnd, "This is a hooked message box!", "My Caption", uType);
}

BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
					 )
{
	switch (ul_reason_for_call) {
		case DLL_PROCESS_ATTACH:
			MessageBox(NULL, "About to hook it", "HOOK STATUS", MB_OK);
			DetourRestoreAfterWith();
			DetourTransactionBegin();
			DetourAttach(&(PVOID&)winMessageBox, hookedMessageBox);
			DetourUpdateThread(GetCurrentThread());
			DetourTransactionCommit();
			MessageBox(NULL, "Function hooked!", "HOOK STATUS", MB_OK);
			break;
		case DLL_THREAD_ATTACH:
			break;
		case DLL_THREAD_DETACH:
			break;
		case DLL_PROCESS_DETACH:
			DetourTransactionBegin();
			DetourUpdateThread(GetCurrentThread());
			DetourDetach(&(PVOID&)winMessageBox, hookedMessageBox);
			DetourTransactionCommit();
			MessageBox(NULL, "Clearing hook!", "HOOK STATUS",MB_OK);
			break;
	}
    return TRUE;
}
</string.h></detours.h></stdio.h></windows.h>