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IRB_REQ_ISOCH_QUERY_RESOURCES structure (1394.h)

  • Article

This structure contains the fields necessary to carry out a IsochQueryResources request.

Syntax

typedef struct _IRB_REQ_ISOCH_QUERY_RESOURCES {
  ULONG         fulSpeed;
  ULONG         BytesPerFrameAvailable;
  LARGE_INTEGER ChannelsAvailable;
} IRB_REQ_ISOCH_QUERY_RESOURCES;

Members

fulSpeed

Specifies the speed flag to use in allocating bandwidth. The possible speed values are SPEED_FLAGS_xxx, where xxx is the approximate transfer rate in megabits per second. Existing hardware supports transfer rates of 100, 200, and 400 MBps.

Transfer Rate Description
SPEED_FLAGS_100 100 Mb/s
SPEED_FLAGS_200 200 Mb/s
SPEED_FLAGS_400 400 Mb/s

BytesPerFrameAvailable

On success, specifies the returned available bandwidth as expressed in bytes per isochronous frame.

ChannelsAvailable

On success, points to a bitmap of available channels.

The highest order bit (bit 63) specifies channel 0, the next bit (bit 62) specifies channel 1, and so on.

Requirements

Requirement Value
Header 1394.h