Enumerating Providers

To retrieve a list of providers that have installed their manifest or MOF classes on the computer, call the TdhEnumerateProviders function.

The following example shows how to enumerate providers.

#include <windows.h>
#include <stdio.h>
#include <tdh.h>

#pragma comment(lib, "tdh.lib")

#define MAX_GUID_SIZE 39

void wmain(void)
{
 DWORD status = ERROR_SUCCESS;
 PROVIDER_ENUMERATION_INFO* penum = NULL; // Buffer that contains provider information
 PROVIDER_ENUMERATION_INFO* ptemp = NULL;
 DWORD BufferSize = 0; // Size of the penum buffer
 HRESULT hr = S_OK; // Return value for StringFromGUID2
 WCHAR StringGuid[MAX_GUID_SIZE];
 DWORD RegisteredMOFCount = 0;
 DWORD RegisteredManifestCount = 0;

 // Retrieve the required buffer size.

 status = TdhEnumerateProviders(penum, &BufferSize);

 // Allocate the required buffer and call TdhEnumerateProviders. The list of 
 // providers can change between the time you retrieved the required buffer 
 // size and the time you enumerated the providers, so call TdhEnumerateProviders
 // in a loop until the function does not return ERROR_INSUFFICIENT_BUFFER.

 while (ERROR_INSUFFICIENT_BUFFER == status)
 {
 ptemp = (PROVIDER_ENUMERATION_INFO*)realloc(penum, BufferSize);
 if (NULL == ptemp)
 {
 wprintf(L"Allocation failed (size=%lu).\n", BufferSize);
 goto cleanup;
 }

 penum = ptemp;
 ptemp = NULL;

 status = TdhEnumerateProviders(penum, &BufferSize);
 }

 if (ERROR_SUCCESS != status)
 {
 wprintf(L"TdhEnumerateProviders failed with %lu.\n", status);
 }
 else
 {
 // Loop through the list of providers and print the provider's name, GUID, 
 // and the source of the information (MOF class or instrumentation manifest).

 for (DWORD i = 0; i < penum->NumberOfProviders; i++)
 {
 hr = StringFromGUID2(penum->TraceProviderInfoArray[i].ProviderGuid, StringGuid, ARRAYSIZE(StringGuid));

 if (FAILED(hr))
 {
 wprintf(L"StringFromGUID2 failed with 0x%x\n", hr);
 goto cleanup;
 }

 wprintf(L"Provider name: %s\nProvider GUID: %s\nSource: %s\n\n",
 (LPWSTR)((PBYTE)(penum)+penum->TraceProviderInfoArray[i].ProviderNameOffset),
 StringGuid,
 (penum->TraceProviderInfoArray[i].SchemaSource) ? L"WMI MOF class" : L"XML manifest");

 (penum->TraceProviderInfoArray[i].SchemaSource) ? RegisteredMOFCount++ : RegisteredManifestCount++;
 }

 wprintf(L"\nThere are %d registered providers; %lu are registered via MOF class and\n%lu are registered via a manifest.\n",
 penum->NumberOfProviders,
 RegisteredMOFCount,
 RegisteredManifestCount);
 }

cleanup:

 if (penum)
 {
 free(penum);
 penum = NULL;
 }
}