So here is my CPP version for you to try:

* * *  vssdircpp.cpp * * *

#include "comutil.h"
#include "atlbase.h"

#include "stdio.h"
#include <iostream>
#include <fstream>
#include <string>

using namespace std;

#import "c:\program files\Microsoft Visual SourceSafe\ssapi.dll"
raw_interfaces_only no_namespace named_guids

int level = 0;

inline void TESTHR(HRESULT x) {if FAILED(x) { IErrorInfo *__pIE;
GetErrorInfo(0, &__pIE); throw _com_error(x, __pIE);} };

void processchildren(IVSSItemPtr item)
{
 level++;

 IVSSItemsPtr children;
 TESTHR(item->get_Items(VARIANT_FALSE, &children));

 long items;
 TESTHR(children->get_Count(&items));

 IVSSItemPtr child;
 for (int i = 1; i <= items; i++)
 {
   TESTHR(children->get_Item(_variant_t(i), &child));

   _bstr_t name;
   TESTHR(child->get_Name(name.GetAddress()));
   cout << string(level, ' ') << (LPTSTR)name << endl;

   int type;
   TESTHR(child->get_Type(&type));
   if ((VSSItemType)type == VSSITEM_PROJECT)
   {
       processchildren(child);
   }
 }
 level--;
}

int main(int argc, char* argv[], char* envp[])
{

 if (argc < 2)
 {
   cerr << "Usage: " << argv[0] << " <path-to-srcsafe.ini>" << endl;
   return 1;
 }

 CoInitialize(NULL);

 CComBSTR srcsafeINI(argv[1]);

 try
 {
   CComPtr<IVSSDatabase> vssDB2;
   TESTHR(vssDB2.CoCreateInstance(CLSID_VSSDatabase));

   TESTHR(vssDB2->Open(srcsafeINI, NULL, NULL));

   IVSSItemPtr item;
   TESTHR(vssDB2->get_VSSItem(CComBSTR(L"$/"), VARIANT_FALSE, &item));

   processchildren(item);
 }
 catch (_com_error &e)
 {
   _bstr_t errMsg = e.Description();
   cerr << _T("** ERROR from Source Safe : ");

   if (errMsg.length() > 0)
   {
     cerr << (wchar_t*)errMsg << endl;
   }
 }

 return 0;
}

1. Start up a VS 2003 Command Prompt
2. compile: cl /EHsc /O2 /MD vssdircpp.cpp

Took 6.686 seconds (as opposed to 56) so 2541 files / sec, which is
closer to your managed version!

I also compiled with the /clr switch as follows
cl /EHa /O2 /MD /clr vssdircpp.cpp

6.5 seconds for the managed C++ 2003 version.  Using reflector, I can
confirm it's all managed code.

However, the same C++ code above compiled for .Net v2.0 yields poor
results - little difference to the 2003 C# version.  I'm going to raise
this as a bug...

Cheers,

Stu