USBListDevice (Function)

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USB functions

USBListDevice (Function)

In french: USBListePériphérique

Returns the list of USB devices currently plugged into the current computer.

Example

// List of USB devices
sList is string = USBListDevice()

// On commence l'exploration sans spécifier d'identifiant
Explore("")

// ----------------------------------------------------------- 
// Explore the entire tree structure
PROCEDURE Explore(sBeginning)
sList is string
sList = USBListDevice(sBeginning)
IF sList <> "" THEN
	sDevice is string
	FOR EACH STRING sDevice OF sList SEPARATED BY CR
	   Trace(USBProperty(sDevice, USBPropertyDeviceDesc))
	   Explore(sDevice)
	END
END

Syntax

<Result> = USBListDevice([<Device Identifier> [, <Options>]])

<Result>: Character string

List of identifiers for the USB devices currently plugged into the current computer. This list has the following format:
<Identifier 1> + CR + <Identifier 2> + CR + ...

If the <Options> parameter corresponds to the USBLstDescription constant, the list of identifiers has the following format:
<Identifier 1> + TAB + <Description 1> + CR + <Identifier 2> + CR + ...

The identifier is used to identify a USB device. This identifier will be used by the USB functions to handle a device.
Empty string ("") if no USB device is found.

<Device Identifier>: Optional character string

Identifier of USB device from which the search will be performed (see the notes)

<Options>: Optional Integer constant

Detailed option of result:
USBLstDescription Used to get the list of identifiers for the USB devices and their description.

Remarks

The USB devices are organized in tree structure.

The roots are the USB controllers. The hubs and the devices are located below. Each device can be "parent" of a "sub-tree".

For example, a USB hub can access the devices plugged into it.

USBListDevice can be called without identifier. In this case, the function returns the identifiers of the USB controllers. If USBListDevice is called again with these identifiers, you will be able to retrieve the list of devices connected to it. This tree structure can be browsed until the function returns "" (empty string).

Component: wd300std.dll