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VIDEO_SHARE_MEMORY structure (ntddvdeo.h)

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The VIDEO_SHARE_MEMORY structure is used in a request to the video miniport driver for a block of user-mode memory to be shared with the specified process.

Syntax

typedef struct _VIDEO_SHARE_MEMORY {
  HANDLE ProcessHandle;
  ULONG  ViewOffset;
  ULONG  ViewSize;
  PVOID  RequestedVirtualAddress;
} VIDEO_SHARE_MEMORY, *PVIDEO_SHARE_MEMORY;

Members

ProcessHandle

Is a handle to the current process. This member is usually set to NtCurrentProcess, a macro defined in Ntddk.h.

ViewOffset

Indicates the byte offset from the beginning of the frame buffer. This member is usually set to 0.

ViewSize

Indicates the size, in bytes, of the frame buffer.

RequestedVirtualAddress

Indicates the location of the requested frame buffer in the process's memory. This member is normally set to NULL, which means the display driver writer does not care about the precise location of the requested memory. If this member is set to a non-NULL value, the display driver writer intends that the frame buffer be located at that address. In this case, the display driver writer must be certain that the location specified is not already in use for another purpose.

Remarks

VIDEO_SHARE_MEMORY is provided so that applications such as Direct Draw can have a view of video memory. Although the display driver is unable to directly provide such access to video memory, it can call into the video miniport driver for this purpose. The display driver does this by sending an IOCTL_VIDEO_SHARE_VIDEO_MEMORY request to the miniport driver. When the miniport driver fulfills this request, it uses the information in the VIDEO_SHARE_MEMORY structure, and fills in a VIDEO_SHARE_MEMORY_INFORMATION structure with the actual location of the requested memory, if no location was specified. When the application no longer needs the shared memory, the display driver can release this memory by making an IOCTL_VIDEO_UNSHARE_VIDEO_MEMORY request, which also uses a VIDEO_SHARE_MEMORY structure as an input buffer.

For structures used in mapping into kernel-mode video memory, see VIDEO_MEMORY and VIDEO_MEMORY_INFORMATION.

Requirements

Requirement Value
Header ntddvdeo.h (include Ntddvdeo.h)

See also

IOCTL_VIDEO_SHARE_VIDEO_MEMORY

IOCTL_VIDEO_UNSHARE_VIDEO_MEMORY

VIDEO_SHARE_MEMORY_INFORMATION