PARCLASS_INFORMATION structure (parallel.h)

Article
04/01/2021

The PARCLASS_INFORMATION structure specifies information about a parallel port, pointers to callback routines to operate a parallel port, and pointers to callback routines to read and write to a parallel device.

Syntax

typedef struct _PARCLASS_INFORMATION {
  PUCHAR                    Controller;
  ULONG                     SpanOfController;
  PDETERMINE_IEEE_MODES     DetermineIeeeModes;
  PNEGOTIATE_IEEE_MODE      NegotiateIeeeMode;
  PTERMINATE_IEEE_MODE      TerminateIeeeMode;
  PPARALLEL_IEEE_FWD_TO_REV IeeeFwdToRevMode;
  PPARALLEL_IEEE_REV_TO_FWD IeeeRevToFwdMode;
  PPARALLEL_READ            ParallelRead;
  PPARALLEL_WRITE           ParallelWrite;
  PVOID                     ParclassContext;
  ULONG                     HardwareCapabilities;
  ULONG                     FifoDepth;
  ULONG                     FifoWidth;
} PARCLASS_INFORMATION, *PPARCLASS_INFORMATION;

Members

Controller

Specifies the base I/O address allocated to a parallel port.

EcrController

SpanOfController

Specifies the range in bytes of I/O address space allocated to a parallel port.

DetermineIeeeModes

Pointer to the PDETERMINE_IEEE_MODES callback routine that determines which IEEE protocols a parallel device supports.

NegotiateIeeeMode

Pointer to the PNEGOTIATE_IEEE_MODE callback routine that negotiates the fastest protocol that the system-supplied bus driver for parallel ports supports from among those specified by the caller.

TerminateIeeeMode

Pointer to the PTERMINATE_IEEE_MODE callback routine that terminates the current IEEE mode and sets the mode to IEEE_COMPATIBILITY.

IeeeFwdToRevMode

Pointer to the PPARALLEL_IEEE_FWD_TO_REV callback routine that changes the transfer mode from forward to reverse.

IeeeRevToFwdMode

Pointer to the PPARALLEL_IEEE_REV_TO_FWD callback routine that changes the transfer mode from reverse to forward.

ParallelRead

Pointer to the PPARALLEL_READ callback routine that a client can use to read from a parallel device.

ParallelWrite

Pointer to the PPARALLEL_WRITE callback routine that a client can use to write to a parallel device.

ParclassContext

Pointer to the device extension of a parallel device's physical device object (PDO).

HardwareCapabilities

Specifies which hardware capabilities are present. HardwareCapabilities is a bitwise OR of one or more of the following flags:

PPT_NO_HARDWARE_PRESENT

PPT_ECP_PRESENT

PPT_EPP_PRESENT

PPT_EPP_32_PRESENT

32-bit reads and writes are supported.

PPT_BYTE_PRESENT

PPT_BIDI_PRESENT

PPT_1284_3_PRESENT

FifoDepth

Specifies the size, in words, of the ECP FIFO. The ECP FIFO word size, in bits, is the value of FifoWidth.

FifoWidth

Specifies the ECP FIFO word size, in bits, which is the number of bits handled in parallel.

ParallelTryselect

ParallelDeSelect

Remarks

A kernel-mode driver can obtain this information from the system-supplied bus driver for parallel ports using an IOCTL_INTERNAL_PARCLASS_CONNECT request. The system-supplied bus driver for parallel ports supplies all the callback routines.

A client uses this information to operate a parallel port and to read and write a parallel device. The callback routines can only be used by a driver that holds a lock on the parent parallel port. A driver obtains a lock by using an IOCTL_INTERNAL_LOCK_PORT request.

For more information, see Connecting to a Parallel Device.

Requirements

Requirement	Value
Header	parallel.h (include Parallel.h)