Simplest driver with visual studio wdk

Question

I'm trying to create a simplest "hello world" driver in Visual Studio 2012 with WDK. The code of Device.c file is this:

#include <ntddk.h>

NTSTATUS DriverEntry(PDRIVER_OBJECT DriverObject, PUNICODE_STRING RegistryPath)
{
    DbgPrint("Hello, World");

    return STATUS_SUCCESS;
}

When building there's an error:

1>Driver.c(3): error C2220: warning treated as error - no 'object' file generated
1>Driver.c(3): warning C4100: 'RegistryPath' : unreferenced formal parameter
1>Driver.c(3): warning C4100: 'DriverObject' : unreferenced formal parameter
2>------ Build started: Project: KMDFSmall Package, Configuration: Win7 Debug x64 ------
2>C:\Program Files (x86)\Windows Kits\8.0\build\WindowsDriver8.0.common.targets(1347,5): error MSB3030: Could not copy the file "Path\To\Projects\SimpleDriver\x64\Win7Debug\KMDFSmall.sys" because it was not found.

What causes these errors?

Answer 1

More recommended way is using UNREFERENCED_PARAMETER() macro, so your function can be changed to:

NTSTATUS DriverEntry(PDRIVER_OBJECT DriverObject, PUNICODE_STRING RegistryPath)
{
    UNREFERENCED_PARAMETER(DriverObject);
    UNREFERENCED_PARAMETER(RegistryPath);

    DbgPrint("Hello, World");

    return STATUS_SUCCESS;
}

Answer 2

The WDK has "Treat warning as error" activated, and unused parameters trigger a warning.

So if you change your code to :

NTSTATUS DriverEntry(PDRIVER_OBJECT /*DriverObject*/, PUNICODE_STRING /*RegistryPath*/)
{
    DbgPrint("Hello, World");

    return STATUS_SUCCESS;
}

it should compile.