SetupDi を使用してハードウェア機器を列挙する方法

   #include <stdio.h>
   #include <windows.h>
   #include <setupapi.h>
   #include <devguid.h>
   #include <regstr.h>

   int main( int argc, char *argv[ ], char *envp[ ] )
   {
       HDEVINFO hDevInfo;
       SP_DEVINFO_DATA DeviceInfoData;
       DWORD i;

       // Create a HDEVINFO with all present devices.
       hDevInfo = SetupDiGetClassDevs(NULL,
           0, // Enumerator
           0,
           DIGCF_PRESENT | DIGCF_ALLCLASSES );
       
       if (hDevInfo == INVALID_HANDLE_VALUE)
       {
           // Insert error handling here.
           return 1;
       }
       
       // Enumerate through all devices in Set.
       
       DeviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA);
       for (i=0;SetupDiEnumDeviceInfo(hDevInfo,i,
           &DeviceInfoData);i++)
       {
           DWORD DataT;
           LPTSTR buffer = NULL;
           DWORD buffersize = 0;
           
           //
           // Call function with null to begin with, 
           // then use the returned buffer size (doubled)
           // to Alloc the buffer. Keep calling until
           // success or an unknown failure.
           //
           //  Double the returned buffersize to correct
           //  for underlying legacy CM functions that 
           //  return an incorrect buffersize value on 
           //  DBCS/MBCS systems.
           // 
           while (!SetupDiGetDeviceRegistryProperty(
               hDevInfo,
               &DeviceInfoData,
               SPDRP_DEVICEDESC,
               &DataT,
               (PBYTE)buffer,
               buffersize,
               &buffersize))
           {
               if (GetLastError() == 
                   ERROR_INSUFFICIENT_BUFFER)
               {
                   // Change the buffer size.
                   if (buffer) LocalFree(buffer);
                   // Double the size to avoid problems on 
                   // W2k MBCS systems per KB 888609. 
                   buffer = LocalAlloc(LPTR,buffersize * 2);
               }
               else
               {
                   // Insert error handling here.
                   break;
               }
           }
           
           printf("Result:[%s]\n",buffer);
           
           if (buffer) LocalFree(buffer);
       }
       
       
       if ( GetLastError()!=NO_ERROR &&
            GetLastError()!=ERROR_NO_MORE_ITEMS )
       {
           // Insert error handling here.
           return 1;
       }
       
       //  Cleanup
       SetupDiDestroyDeviceInfoList(hDevInfo);
       
       return 0;
   }
				

    hDevInfo = SetupDiGetClassDevs(NULL,
        REGSTR_KEY_PCIENUM, // Enumerator
        0,
        DIGCF_PRESENT | DIGCF_ALLCLASSES );