Hidapi
A Simple library for communicating with USB and Bluetooth HID devices on Linux, Mac, and Windows.
Install / Use
/learn @signal11/HidapiREADME
HIDAPI library for Windows, Linux, FreeBSD and Mac OS X
=========================================================
About
HIDAPI is a multi-platform library which allows an application to interface with USB and Bluetooth HID-Class devices on Windows, Linux, FreeBSD, and Mac OS X. HIDAPI can be either built as a shared library (.so or .dll) or can be embedded directly into a target application by adding a single source file (per platform) and a single header.
HIDAPI has four back-ends: * Windows (using hid.dll) * Linux/hidraw (using the Kernel's hidraw driver) * Linux/libusb (using libusb-1.0) * FreeBSD (using libusb-1.0) * Mac (using IOHidManager)
On Linux, either the hidraw or the libusb back-end can be used. There are tradeoffs, and the functionality supported is slightly different.
Linux/hidraw (linux/hid.c): This back-end uses the hidraw interface in the Linux kernel. While this back-end will support both USB and Bluetooth, it has some limitations on kernels prior to 2.6.39, including the inability to send or receive feature reports. In addition, it will only communicate with devices which have hidraw nodes associated with them. Keyboards, mice, and some other devices which are blacklisted from having hidraw nodes will not work. Fortunately, for nearly all the uses of hidraw, this is not a problem.
Linux/FreeBSD/libusb (libusb/hid.c): This back-end uses libusb-1.0 to communicate directly to a USB device. This back-end will of course not work with Bluetooth devices.
HIDAPI also comes with a Test GUI. The Test GUI is cross-platform and uses Fox Toolkit (http://www.fox-toolkit.org). It will build on every platform which HIDAPI supports. Since it relies on a 3rd party library, building it is optional but recommended because it is so useful when debugging hardware.
What Does the API Look Like?
The API provides the the most commonly used HID functions including sending and receiving of input, output, and feature reports. The sample program, which communicates with a heavily hacked up version of the Microchip USB Generic HID sample looks like this (with error checking removed for simplicity):
#ifdef WIN32 #include <windows.h> #endif #include <stdio.h> #include <stdlib.h> #include "hidapi.h"
#define MAX_STR 255
int main(int argc, char* argv[]) { int res; unsigned char buf[65]; wchar_t wstr[MAX_STR]; hid_device *handle; int i;
// Initialize the hidapi library
res = hid_init();
// Open the device using the VID, PID,
// and optionally the Serial number.
handle = hid_open(0x4d8, 0x3f, NULL);
// Read the Manufacturer String
res = hid_get_manufacturer_string(handle, wstr, MAX_STR);
wprintf(L"Manufacturer String: %s\n", wstr);
// Read the Product String
res = hid_get_product_string(handle, wstr, MAX_STR);
wprintf(L"Product String: %s\n", wstr);
// Read the Serial Number String
res = hid_get_serial_number_string(handle, wstr, MAX_STR);
wprintf(L"Serial Number String: (%d) %s\n", wstr[0], wstr);
// Read Indexed String 1
res = hid_get_indexed_string(handle, 1, wstr, MAX_STR);
wprintf(L"Indexed String 1: %s\n", wstr);
// Toggle LED (cmd 0x80). The first byte is the report number (0x0).
buf[0] = 0x0;
buf[1] = 0x80;
res = hid_write(handle, buf, 65);
// Request state (cmd 0x81). The first byte is the report number (0x0).
buf[0] = 0x0;
buf[1] = 0x81;
res = hid_write(handle, buf, 65);
// Read requested state
res = hid_read(handle, buf, 65);
// Print out the returned buffer.
for (i = 0; i < 4; i++)
printf("buf[%d]: %d\n", i, buf[i]);
// Finalize the hidapi library
res = hid_exit();
return 0;
}
If you have your own simple test programs which communicate with standard hardware development boards (such as those from Microchip, TI, Atmel, FreeScale and others), please consider sending me something like the above for inclusion into the HIDAPI source. This will help others who have the same hardware as you do.
License
HIDAPI may be used by one of three licenses as outlined in LICENSE.txt.
Download
HIDAPI can be downloaded from github git clone git://github.com/signal11/hidapi.git
Build Instructions
This section is long. Don't be put off by this. It's not long because it's complicated to build HIDAPI; it's quite the opposite. This section is long because of the flexibility of HIDAPI and the large number of ways in which it can be built and used. You will likely pick a single build method.
HIDAPI can be built in several different ways. If you elect to build a shared library, you will need to build it from the HIDAPI source distribution. If you choose instead to embed HIDAPI directly into your application, you can skip the building and look at the provided platform Makefiles for guidance. These platform Makefiles are located in linux/ libusb/ mac/ and windows/ and are called Makefile-manual. In addition, Visual Studio projects are provided. Even if you're going to embed HIDAPI into your project, it is still beneficial to build the example programs.
Prerequisites:
Linux:
-------
On Linux, you will need to install development packages for libudev,
libusb and optionally Fox-toolkit (for the test GUI). On
Debian/Ubuntu systems these can be installed by running:
sudo apt-get install libudev-dev libusb-1.0-0-dev libfox-1.6-dev
If you downloaded the source directly from the git repository (using
git clone), you'll need Autotools:
sudo apt-get install autotools-dev autoconf automake libtool
FreeBSD:
---------
On FreeBSD you will need to install GNU make, libiconv, and
optionally Fox-Toolkit (for the test GUI). This is done by running
the following:
pkg_add -r gmake libiconv fox16
If you downloaded the source directly from the git repository (using
git clone), you'll need Autotools:
pkg_add -r autotools
Mac:
-----
On Mac, you will need to install Fox-Toolkit if you wish to build
the Test GUI. There are two ways to do this, and each has a slight
complication. Which method you use depends on your use case.
If you wish to build the Test GUI just for your own testing on your
own computer, then the easiest method is to install Fox-Toolkit
using ports:
sudo port install fox
If you wish to build the TestGUI app bundle to redistribute to
others, you will need to install Fox-toolkit from source. This is
because the version of fox that gets installed using ports uses the
ports X11 libraries which are not compatible with the Apple X11
libraries. If you install Fox with ports and then try to distribute
your built app bundle, it will simply fail to run on other systems.
To install Fox-Toolkit manually, download the source package from
http://www.fox-toolkit.org, extract it, and run the following from
within the extracted source:
./configure && make && make install
Windows:
---------
On Windows, if you want to build the test GUI, you will need to get
the hidapi-externals.zip package from the download site. This
contains pre-built binaries for Fox-toolkit. Extract
hidapi-externals.zip just outside of hidapi, so that
hidapi-externals and hidapi are on the same level, as shown:
Parent_Folder
|
+hidapi
+hidapi-externals
Again, this step is not required if you do not wish to build the
test GUI.
Building HIDAPI into a shared library on Unix Platforms:
On Unix-like systems such as Linux, FreeBSD, Mac, and even Windows, using Mingw or Cygwin, the easiest way to build a standard system-installed shared library is to use the GNU Autotools build system. If you checked out the source from the git repository, run the following:
./bootstrap
./configure
make
make install <----- as root, or using sudo
If you downloaded a source package (ie: if you did not run git clone), you can skip the ./bootstrap step.
./configure can take several arguments which control the build. The two most likely to be used are: --enable-testgui Enable build of the Test GUI. This requires Fox toolkit to be installed. Instructions for installing Fox-Toolkit on each platform are in the Prerequisites section above.
--prefix=/usr
Specify where you want the output headers and libraries to
be installed. The example above will put the headers in
/usr/include and the binaries in /usr/lib. The default is to
install into /usr/local which is fine on most systems.
Building the manual way on Unix platforms:
Manual Makefiles are provided mostly to give the user and idea what it takes to build a program which embeds HIDAPI directly inside of it. These should really be used as examples only. If you want to build a system-wide shared library, use the Autotools method described above.
To build HIDAPI using the manual makefiles, change to the directory
of your platform and run make. For example, on Linux run:
cd linux/
make -f Makefile-manual
To build the Test GUI using the manual makefiles:
cd testgui/
make -f Makefile-manual
Building on Windows:
To build the HIDAPI DLL on Windows using Visual Studio, build the .sln file in the windows/ directory.
To build the Test GUI on windows using Visual Studio, build the .sln file in the testgui/ directory.
To build HIDAPI using MinGW or Cygwin using Autotools, use the instructions in the section titled "Building HIDAPI into a shared library on Unix Platforms" above. Note that building the Test GUI with MinGW or Cygwin will require the Windows procedure in the Prerequisites section above (ie: hidapi-externals.zip).
To build HIDAPI using MinGW using the Manual Makefiles, see the section "Building the manual way on Unix platforms" above.
HIDAPI can also be built using the Windows DDK (now also called the Windows Driver Kit or WDK). This method was originally required for the HIDAPI build but not anymore. How
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