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# IOUSBGetEndpointBurstSize

Extracts the burst size from endpoint descriptors.

```
uint32_t IOUSBGetEndpointBurstSize(uint32_t usbDeviceSpeed, const IOUSBEndpointDescriptor *descriptor, const IOUSBSuperSpeedEndpointCompanionDescriptor *companionDescriptor, const IOUSBSuperSpeedPlusIsochronousEndpointCompanionDescriptor *sspCompanionDescriptor);
```

## Parameters

`usbDeviceSpeed`

The operational speed of the device.

`descriptor`

The endpoint descriptor to parse.

`companionDescriptor`

The SuperSpeed endpoint companion descriptor to parse, or `NULL`.

`sspCompanionDescriptor`

The SuperSpeed Plus isochronous endpoint companion descriptor to parse, or `NULL`.

## Return Value

The burst size in bytes.

## Discussion

This method parses endpoint descriptors to determine burst size, which includes mult and burst factors as applicable. SuperSpeed Plus isochronous endpoints return the `dwBytesPerInterva`l field from the [`IOUSBSuperSpeedPlusIsochronousEndpointCompanionDescriptor`](/documentation/USBDriverKit/IOUSBSuperSpeedPlusIsochronousEndpointCompanionDescriptor) parameter.

---

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