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NC:parallel.PPARALLEL_FREE_ROUTINE

PPARALLEL_FREE_ROUTINE (parallel.h)

The PPARALLEL_FREE_ROUTINE-typed callback routine frees a parallel port. The system-supplied function driver for parallel ports supplies this routine.

parports\pparallel_free_routine.htm

parports

02/15/2018

PPARALLEL_FREE_ROUTINE callback

(*PPARALLEL_FREE_ROUTINE), (*PPARALLEL_FREE_ROUTINE) callback function [Parallel Ports], cisspd_5f5bcbed-0df6-4b2a-ab88-a26f48976ad7.xml, parallel/(*PPARALLEL_FREE_ROUTINE), parports.pparallel_free_routine

parallel.h

Parallel.h

Desktop

<=DISPATCH_LEVEL

Windows

RILGBATOKEN, *LPRILGBATOKEN

PPARALLEL_FREE_ROUTINE

parallel/PPARALLEL_FREE_ROUTINE

APIRef

kbSyntax

UserDefined

parallel.h

PPARALLEL_FREE_ROUTINE

PPARALLEL_FREE_ROUTINE callback

-description

The PPARALLEL_FREE_ROUTINE-typed callback routine frees a parallel port. The system-supplied function driver for parallel ports supplies this routine.

-parameters

-param FreeContext [in]

Pointer to the device extension of a parallel port's functional device object (FDO).

-prototype

typedef VOID (*PPARALLEL_FREE_ROUTINE)(
  _In_ PVOID FreeContext
);

-remarks

To obtain a pointer to the system-supplied PPARALLEL_FREE_ROUTINE callback, a kernel-mode driver uses an IOCTL_INTERNAL_GET_PARALLEL_PORT_INFO request, which returns a PARALLEL_PORT_INFORMATION structure. The FreePort member of the PARALLEL_PORT_INFORMATION structure is a pointer to this callback.

The driver should allocate a parallel port before freeing it. A driver can use PPARALLEL_QUERY_WAITERS_ROUTINE to determine the number of clients that are waiting to allocate the parallel port, and PPARALLEL_TRY_ALLOCATE_ROUTINE to try to allocate the parallel port.