USBDev_AltSettingQtyGet

Owned by Former user (Deleted)
Last updated: Dec 03, 2020 by WES Admin

Description

Get number of alternate settings for the specified interface.

Files

usbdev_api.c

Prototype

UCHAR  USBDev_AltSettingQtyGet (HANDLE   dev,
                                UCHAR    if_nbr,
                                DWORD   *p_err);


Arguments

dev

General handle to device.

if_nbr

Interface number.

p_err

Pointer to variable that will receive the return error code from this function:

ERROR_SUCCESS
ERROR_INVALID_HANDLE
ERROR_INVALID_PARAMETER

Returned Value

Number of alternate setting, if NO error(s).

0, otherwise.

Callers

Application.

Notes / Warnings

  1. An interface may include alternate settings that allow the endpoints and/or their characteristics to be varied after the device has been configured. The default setting for an interface is always alternate setting zero. Alternate settings allow a portion of the device configuration to be varied while other interfaces remain in operation.
  2. The number of alternate settings gotten can be used to open a pipe associated with a certain alternate interface.