USBDev_DevQtyGet

Description

Get number of devices belonging to the specified GUID.

Files

usbdev_api.c

Prototype

DWORD  USBDev_DevQtyGet (const  GUID    guid_dev_if,
                                DWORD  *p_err);

Arguments

guid_dev_if

Device interface class GUID.

p_err

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

ERROR_SUCCESS

Returned Value

Number of devices for the provided GUID, if NO error(s).

0, otherwise.

Callers

Application.

Notes / Warnings

The function USBDev_DevQtyGet() uses the concept of device information set. A device information set consists of device information elements for all the devices that belong to some device setup class or device interface class. The GUID passed to USBDev_DevQtyGet() function is a device interface class. Internally by using some control options the function retrieves the device information set which represents a list of all devices present in the system and registered under the specified GUID. More details about the device information set can be found at http://msdn.microsoft.com/en-us/library/ff541247(VS.85).aspx.