Intel Extensible Firmware Interface - Manual (Page 169)

Services — Boot Services
Version 1.10 12/01/02 5-71
If NoHandles is NULL , then EFI_INVALID_PARAMETER is returned.
If Buffer is NULL , then EFI_INVALID_PARAMETER is returned.
If there are no handles in the handle database that match the search criteria, then
EFI_NOT_FOUND is returned.
If there are not enough resources available to allocate Buffer , then EFI_OUT_OF_RESOURCES
is returned.
Status Codes Returned
EFI_SUCCESS The array of handles was returned in Buffer , and the number of
handles in Buffer was returned in NoHandles .
EFI_INVALID_PARAMETER NoHandles is NULL
EFI_INVALID_PARAMETER Buffer is NULL
EFI_NOT_FOUND No handles match the search.
EFI_OUT_OF_RESOURCES There is not enough pool memory to store the matching results.
Examples
//
// The following example traverses the entire handle database.
First all of
// the handles in the handle database are retrieved by using
// LocateHandleBuffer().
Then it uses ProtocolsPerHandle() to retrieve the
// list of protocol GUIDs attached to each handle. Then it uses OpenProtocol()
// to get the protocol instance associated with each protocol GUID on the
// handle.
Finally, it uses OpenProtocolInformation() to retrieve the list of
// agents that have opened the protocol on the handle. The caller of these
// functions must make sure that they free the return buffers with FreePool()
// when they are done.
//
EFI_STATUS Status;
EFI_BOOT_SERVICES_TABLE *gBS;
EFI_HANDLE ImageHandle;
UINTN HandleCount;
EFI_HANDLE *HandleBuffer;
UINTN HandleIndex;
EFI_GUID **ProtocolGuidArray;
UINTN ArrayCount;
UINTN ProtocolIndex;
EFI_OPEN_PROTOCOL_INFORMATION_ENTRY *OpenInfo;
UINTN
OpenInfoCount;
UINTN OpenInfoIndex;
//
// Retrieve the list of all handles from the handle database
//
Status = gBS->LocateHandleBuffer (
AllHandles,
NULL,
NULL,
&HandleCount,
&HandleBuffer
);
if (!EFI_ERROR (Status)) {
for (HandleIndex = 0; HandleIndex < HandleCount; HandleIndex++) {