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mcuee edited this page Oct 13, 2021 · 69 revisions

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This project adds Windows platform support to the libusb Open Source library, in order to help developers easily communicate with USB devices on Windows. Currently it supports the WinUSB and HID drivers for generic USB device access as well as the libusb-win32 and libusbK drivers.

Take note libusb-win32 and libusbK are separated projects. libusb-win32 is a Windows only project which provide libusb-0.1 API compatible library for Windows and the associated kernel driver libusb0.sys. libusbK is a Windows only project which provides a new set of API for Windows (supporting WinUSB, libusb0.sys and libusbk.sys) and kernel driver libusbK.sys.

Binary Snapshots

Pre-built binary snapshots are provided in the Sourceforge files directory along with the source code archive. Since 1.0.21 release, they are also in github release page.

The pre-built Windows binaries are provided AS IS for your convenience, generated for the following environments:

  • Microsoft Visual Studio and DDK/WDK → MS32(32 bit) and MS64 (64 bit) directories
  • MinGW -> MinGW32 (32 bit) and MinGW64 (64 bit) directories
Note that these archives are provided in the 7z format so you may have to install ​7-zip.

You may want to build from source if you encounter compatibility issues with the pre-built binary.

vcpkg port

vcpkg now includes libusb ports.

Installing and building libusb via vcpkg:

You can download and install libusb using the vcpkg dependency manager:

    git clone
    cd vcpkg
    .\vcpkg integrate install
    .\vcpkg install libusb

The libusb port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.

msys2 MinGW-w64 32bit/64bit package

msys2 has the libusb package. Please contact msys2 project if you encountered issues with the msys2 package. It is recommended you use pkg-config (libusb-1.0.pc) if you use MSYS2 or other MinGW-w64 distributions.

Reference: how to use libusb under MinGW-w64?

Supported Environments

Supported systems are all Windows platforms, starting with Windows XP, and including 64 bit versions, with the following exceptions:

  • Windows 2003 (Microsoft does not support WinUSB on 32bit/64bit Windows 2003)
  • Windows XP 64 bit (Microsoft does not officially support WinUSB on 64bit Windows XP)
Note: Windows XP support is dropped in libusb 1.0.24.

USB 3.x Support

libusb supports USB 3.x controllers and devices on Windows. Proprietary vendor controller drivers for Windows 7 and earlier as well as the Microsoft controller xHCI driver for Windows 8/8.1/10 are supported. If you are are using Windows 7 or earlier version, you will be using vendor driver. Make sure you upgrade to the latest version of the driver if you encounter problems.

.NET support

A .NET version of libusb, called LibUsbDotNet, based on libusb 1.0. If you plan to use libusb in a .NET project, make sure you check out the latest release at github.

How to use libusb on Windows

Driver Installation

If your target device is not HID, and your device is not using WinUSB driver, you must install a driver before you can communicate with it using libusb. Currently, this means installing one of Microsoft's WinUSB, libusb-win32 or libusbK drivers. Two options are available:

  • Recommended: Use the most recent version of Zadig, an Automated Driver Installer GUI application for WinUSB (recommended), libusb-win32 (not working well, not recommended) and libusbK (only if you hit WinUSB limitations, and in case of isochronous transfer since the support of WinUSB isochronous transfer is not so mature yet).
  • For version 1.0.21 or later, you can also use usbdk backend. usbdk provides another driver option for libusb Windows backend. For 1.0.21, usbdk is a compile-time option, but it becomes a runtime option from version 1.0.22 onwards, so you need to specify the usbdk backend using something like the following.
libusb_context * ctx = NULL;
libusb_set_option(ctx, LIBUSB_OPTION_USE_USBDK);
Note that if your device is using libusb-win32 driver (libusb0.sys), you will also need to install the libusbK DLL, as all libusb0.sys accesses are done through it. One way to install/update libusbK.dll is to install libusbk development kit (libusbK-x.x.x.x-setup.exe from Sourceforge site and choose to update the system files during the installation. However the support of libusb-win32/libusb0.sys (especially the filter mode) is not working well now, therefore you should not use libusb0.sys for now and you should upgrade to WinUSB or libusbk instead whenever possible.

Development Considerations

The handling of composite devices under Windows is done with multiple drivers, that are children of the usbccgp.sys driver (Composite Generic Parent), as this is the default for the OS. If needed, it is also possible to replace the composite parent driver to access the device. Zadig can be used for this purpose.

Because Windows does not provide a native poll() function, and cygwin is the only development environment that provides such a call, the use of libusb file descriptors with poll() on cygwin is NOT supported. In a future version of libusb, we should provide better handling of native Windows events, but this will require a redesign of the libusb API, so it probably won't occur before libusb 2.0.

Known Restrictions

  • WinUSB cannot be used to send an actual reset command to an USB device. This is a limitation of WinUSB.
  • WinUSB and libusbK cannot be used to set a device configuration that is different from the first one. This is a limitation of KMDF USB I/O Target.
  • WinUSB does not support multiple concurrent applications (as per the Microsoft Windows Hardware Drivers documentation). libusbk driver allows this but it may have the limitation that you can claim the interface multiple times ( libusb-win32 driver will also allow this but it is not recommended to be used due to multiple issues reported.
  • WinUSB does not support isochronous transfers under Windows XP/Vista/7/8. WinUSB under Windows 8.1 or later supports isochronous transfer. libusb Windows supports isochronous transfer using the usbdk backend from version 1.0.21. libusb-1.0.22 adds isochronous support using libsubK driver. libusb-1.0.23 adds isochronous transfer support for WinUSB (Windows 8.1/10 or later) but the support may not be that mature.
  • WinUSB allows setting up different pipe policy and RAW_IO can be useful in some use cases. Unfortunately it will make the WinUSB backend pretty complicated so this is not supported. why not WinUSB RAW_IO pipe policy?
  • With WinUSB, when LIBUSB_RECIPIENT_INTERFACE is used for the transfer, the WinUSB DLL forces the low byte of wIndex to the interface number, regardless of what you set it to.
    • This is not a real limitation though, please refer to the OSR threads. From Tim Roberts answer in that thread:
    • One can also argue that this is a security measure. The USB spec requires that the low byte of wIndex be set to the interface number when the recipient is set to "interface". Devices that use that field for other purposes are broken.
  • HID keyboards and mice cannot be accessed using the native HID driver as Windows reserves exclusive access to them.
  • Multiple HID top level collections are currently not supported (only the first top level collection will be used).
  • The HID Report Descriptors provided by libusb are recomposed and may present minor differences from the actual ones, as the Windows HID API does not allow to read them directly from the device.
  • Windows HID API does not support custom Control Transfer, everything needs to be done through report. Please check out the discussion here.
  • Because there is no native poll() on Windows, the ability to return externally pollable file descriptors on Windows libusb_get_pollfd() returns an error.
  • If you use a composite device, and plan to install a libusb compatible driver for any of the interfaces, you should ensure that your driver package adds a Device Interface GUID in the registry, as proper enumeration of composite devices in libusb depends on it. This is typically achieved by adding something like the following in your inf:
    This is in particular a problem with libusb-win32's inf-wizard which will be deprecated by libusb-win32 project. Please use Zadig instead.
  • libusb0.sys and libusbk.sys access is done through the libusbK DLL, therefore, if you plan to use the libusb-win32/libusb0.sys or libusbK/libusbk.sys driver in libusb, you must have that library installed. If using a recent version of Zadig, you should not have to do anything, at it will install the library for you. However the support of libusb0.sys is not ready, therefore you should not use libusb-win32/libusb0.sys for now.
  • uhubctl will not work under Windows. Please refer to Issue #391 due to limitation of the underlying drivers (libusb0.sys, libusbk.sys, usbdk and WinUSB) with regard to USB Hubs.

Development Links