Why do EnumDomains/NextDomain loop forever? - c++

Question

The following simple code can be directly run in Visual Studio C++ console project.
It will loop forever because the NextDomain will always return the same IUnknown *
According to Microsoft, it should return NULL if the enumeration reaches end. See https://learn.microsoft.com/en-us/dotnet/framework/unmanaged-api/hosting/icorruntimehost-nextdomain-method
However, the NULL is never reached. It seems that it never return the NextDomain but keep returning the same domain.
Is there anything wrong? Thanks.
#include <iostream>
#include <Windows.h>
#include <metahost.h>
#include <mscoree.h>
#pragma comment(lib, "mscoree.lib")
int main()
{
ICLRMetaHost* clrMetaHost = NULL;
ICLRRuntimeInfo* clrRuntimeInfo = NULL;
ICorRuntimeHost* clrCorRuntimeHost = NULL;
do {
if (FAILED(CLRCreateInstance(CLSID_CLRMetaHost, IID_PPV_ARGS(&clrMetaHost))))
{
std::cout << "failed 1" << std::endl;
break;
}
if (FAILED(clrMetaHost->GetRuntime(L"v2.0.50727", IID_PPV_ARGS(&clrRuntimeInfo))))
{
if (FAILED(clrMetaHost->GetRuntime(L"v4.0.30319", IID_PPV_ARGS(&clrRuntimeInfo))))
{
std::cout << "failed 2" << std::endl;
break;
}
}
if (FAILED(clrRuntimeInfo->GetInterface(CLSID_CorRuntimeHost, IID_PPV_ARGS(&clrCorRuntimeHost))))
{
std::cout << "failed 3" << std::endl;
break;
}
if (FAILED(clrCorRuntimeHost->Start()))
{
std::cout << "failed 4" << std::endl;
break;
}
HDOMAINENUM hDomainEnum = nullptr;
if (FAILED(clrCorRuntimeHost->EnumDomains(&hDomainEnum))) {
std::cout << "failed 5" << std::endl;
break;
}
IUnknown* domain;
while (SUCCEEDED(clrCorRuntimeHost->NextDomain(hDomainEnum, &domain))
&& domain != NULL) {
std::cout << "why loop forever here?" << std::endl;
domain->Release();
}
if (FAILED(clrCorRuntimeHost->CloseEnum(hDomainEnum))) {
std::cout << "failed 6" << std::endl;
}
break;
} while (0);
if (clrCorRuntimeHost != NULL) clrCorRuntimeHost->Release();
if (clrRuntimeInfo != NULL) clrRuntimeInfo->Release();
if (clrMetaHost != NULL) clrMetaHost->Release();
return 0;
}

Answer 1

Return code from most enumerators is S_OK to continue and S_FALSE when it did not succeed. S_FALSE is not a fail code.
while (S_OK == clrCorRuntimeHost->NextDomain(hDomainEnum, &domain))
&& domain != NULL) {
std::cout << "why loop forever here?" << std::endl;
domain->Release();
}