PPARALLEL_WRITE - NtDoc
Native API online documentation, based on the System Informer
(formerly Process Hacker) phnt
headers
// parallel.h
PPARALLEL_WRITE PparallelWrite;
NTSTATUS PparallelWrite(
[in] PVOID Context,
[in] PVOID Buffer,
[in] ULONG NumBytesToWrite,
[out] PULONG NumBytesWritten,
[in] UCHAR Channel
)
{...}
View the official Windows Driver Kit DDI referenceNo description available.
The PPARALLEL_WRITE-typed callback routine writes data to a parallel device. The system-supplied bus driver for parallel ports supplies this routine.
Context [in]Pointer to the device extension of a parallel device's physical device object (PDO).
Buffer [in]Pointer to a caller-allocated write buffer.
NumBytesToWrite [in]Specifies the number of bytes to copy from the write buffer to the parallel device. Must be less than or equal to the number of bytes in the caller-allocated write buffer.
NumBytesWritten [out]Specifies the number of bytes that were actually copied from the caller-allocated write buffer to the parallel device.
Channel [in]Not used.
| Return code | Description |
|---|---|
| STATUS_SUCCESS | The caller-supplied data was successfully transferred to the device. |
| STATUS_*Xxx* | An internal operation resulted in an NTSTATUS error. |
typedef NTSTATUS ( *PPARALLEL_WRITE)(
_In_ PVOID Context,
_In_ PVOID Buffer,
_In_ ULONG NumBytesToWrite,
_Out_ PULONG NumBytesWritten,
_In_ UCHAR Channel
);
To obtain a pointer to the system-supplied PPARALLEL_WRITE callback, a kernel-mode driver uses an IOCTL_INTERNAL_PARCLASS_CONNECT request, which returns a PARCLASS_INFORMATION structure. The ParallelWrite member of the PARCLASS_INFORMATION structure is a pointer to this callback.
A client can only use this routine if it has a lock on a parallel port. A client obtains a lock on a parallel port by using an IOCTL_INTERNAL_LOCK_PORT request.
The PPARALLEL_WRITE callback runs in the caller's thread at the IRQL of the caller.