RtlIoEncodeMemIoResource function (wdm.h)
The RtlIoEncodeMemIoResource routine updates an IO_RESOURCE_DESCRIPTOR structure to describe a range of memory or I/O port addresses.
Syntax
NTSYSAPI NTSTATUS RtlIoEncodeMemIoResource(
[in] PIO_RESOURCE_DESCRIPTOR Descriptor,
[in] UCHAR Type,
[in] ULONGLONG Length,
[in] ULONGLONG Alignment,
[in] ULONGLONG MinimumAddress,
[in] ULONGLONG MaximumAddress
);
Parameters
[in] Descriptor
A pointer to the IO_RESOURCE_DESCRIPTOR structure to update.
[in] Type
The resource type of the address range. This parameter can be CmResourceTypeMemory, CmResourceTypeMemoryLarge, or CmResourceTypePort.
[in] Length
The length, in bytes, of the range of assignable addresses.
[in] Alignment
The alignment, in bytes, of the starting address of address range.
[in] MinimumAddress
The minimum address that can be assigned to the device.
[in] MaximumAddress
The maximum address that can be assigned to the device.
Return value
RtlIoEncodeMemIoResource returns an NTSTATUS value. This routine might return one of the following values:
| Return code | Description |
|---|---|
|
The IO_RESOURCE_DESCRIPTOR structure was updated. |
|
The specified value for Length or Alignment could not be encoded in an IO_RESOURCE_DESCRIPTOR structure. |
|
One or more of the specified parameters were invalid. |
Remarks
Addresses that are larger than 32 bits in length must satisfy certain alignment restrictions, or else the routine returns STATUS_UNSUCCESSFUL.
| Address length | Alignment restriction |
|---|---|
| 40 bits | Lowest 8 bits must be zero. |
| 48 bits | Lowest 16 bits must be zero. |
| 64 bits | Lowest 32 bits must be zero. |
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available in Windows Vista and later versions of Windows. |
| Target Platform | Universal |
| Header | wdm.h (include Wdm.h, Ntddk.h, Ntifs.h) |
| Library | NtosKrnl.lib |
| DLL | NtosKrnl.exe |
| IRQL | Any level |