Adding third party library hidapi

third_party/hidapi/hidapi_linux.c

+/*******************************************************
+ HIDAPI - Multi-Platform library for
+ communication with HID devices.
+
+ Alan Ott
+ Signal 11 Software
+
+ 8/22/2009
+ Linux Version - 6/2/2009
+
+ Copyright 2009, All Rights Reserved.
+
+ At the discretion of the user of this library,
+ this software may be licensed under the terms of the
+ GNU Public License v3, a BSD-Style license, or the
+ original HIDAPI license as outlined in the LICENSE.txt,
+ LICENSE-gpl3.txt, LICENSE-bsd.txt, and LICENSE-orig.txt
+ files located at the root of the source distribution.
+ These files may also be found in the public source
+ code repository located at:
+        http://github.com/signal11/hidapi .
+********************************************************/
+
+/* C */
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <locale.h>
+#include <errno.h>
+
+/* Unix */
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/utsname.h>
+#include <fcntl.h>
+#include <poll.h>
+
+/* Linux */
+#include <linux/hidraw.h>
+#include <linux/version.h>
+#include <linux/input.h>
+#include <libudev.h>
+
+#include "hidapi.h"
+
+/* Definitions from linux/hidraw.h. Since these are new, some distros
+   may not have header files which contain them. */
+#ifndef HIDIOCSFEATURE
+#define HIDIOCSFEATURE(len)    _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x06, len)
+#endif
+#ifndef HIDIOCGFEATURE
+#define HIDIOCGFEATURE(len)    _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x07, len)
+#endif
+
+
+/* USB HID device property names */
+const char *device_string_names[] = {
+        "manufacturer",
+        "product",
+        "serial",
+};
+
+/* Symbolic names for the properties above */
+enum device_string_id {
+        DEVICE_STRING_MANUFACTURER,
+        DEVICE_STRING_PRODUCT,
+        DEVICE_STRING_SERIAL,
+
+        DEVICE_STRING_COUNT,
+};
+
+struct hid_device_ {
+        int device_handle;
+        int blocking;
+        int uses_numbered_reports;
+};
+
+
+static __u32 kernel_version = 0;
+
+static hid_device *new_hid_device(void)
+{
+        hid_device *dev = calloc(1, sizeof(hid_device));
+        dev->device_handle = -1;
+        dev->blocking = 1;
+        dev->uses_numbered_reports = 0;
+
+        return dev;
+}
+
+
+/* The caller must free the returned string with free(). */
+static wchar_t *utf8_to_wchar_t(const char *utf8)
+{
+        wchar_t *ret = NULL;
+
+        if (utf8) {
+                size_t wlen = mbstowcs(NULL, utf8, 0);
+                if ((size_t) -1 == wlen) {
+                        return wcsdup(L"");
+                }
+                ret = calloc(wlen+1, sizeof(wchar_t));
+                mbstowcs(ret, utf8, wlen+1);
+                ret[wlen] = 0x0000;
+        }
+
+        return ret;
+}
+
+/* Get an attribute value from a udev_device and return it as a whar_t
+   string. The returned string must be freed with free() when done.*/
+static wchar_t *copy_udev_string(struct udev_device *dev, const char *udev_name)
+{
+        return utf8_to_wchar_t(udev_device_get_sysattr_value(dev, udev_name));
+}
+
+/* uses_numbered_reports() returns 1 if report_descriptor describes a device
+   which contains numbered reports. */
+static int uses_numbered_reports(__u8 *report_descriptor, __u32 size) {
+        unsigned int i = 0;
+        int size_code;
+        int data_len, key_size;
+
+        while (i < size) {
+                int key = report_descriptor[i];
+
+                /* Check for the Report ID key */
+                if (key == 0x85/*Report ID*/) {
+                        /* This device has a Report ID, which means it uses
+                           numbered reports. */
+                        return 1;
+                }
+
+                //printf("key: %02hhx\n", key);
+
+                if ((key & 0xf0) == 0xf0) {
+                        /* This is a Long Item. The next byte contains the
+                           length of the data section (value) for this key.
+                           See the HID specification, version 1.11, section
+                           6.2.2.3, titled "Long Items." */
+                        if (i+1 < size)
+                                data_len = report_descriptor[i+1];
+                        else
+                                data_len = 0; /* malformed report */
+                        key_size = 3;
+                }
+                else {
+                        /* This is a Short Item. The bottom two bits of the
+                           key contain the size code for the data section
+                           (value) for this key.  Refer to the HID
+                           specification, version 1.11, section 6.2.2.2,
+                           titled "Short Items." */
+                        size_code = key & 0x3;
+                        switch (size_code) {
+                        case 0:
+                        case 1:
+                        case 2:
+                                data_len = size_code;
+                                break;
+                        case 3:
+                                data_len = 4;
+                                break;
+                        default:
+                                /* Can't ever happen since size_code is & 0x3 */
+                                data_len = 0;
+                                break;
+                        };
+                        key_size = 1;
+                }
+
+                /* Skip over this key and it's associated data */
+                i += data_len + key_size;
+        }
+
+        /* Didn't find a Report ID key. Device doesn't use numbered reports. */
+        return 0;
+}
+
+/*
+ * The caller is responsible for free()ing the (newly-allocated) character
+ * strings pointed to by serial_number_utf8 and product_name_utf8 after use.
+ */
+static int
+parse_uevent_info(const char *uevent, int *bus_type,
+        unsigned short *vendor_id, unsigned short *product_id,
+        char **serial_number_utf8, char **product_name_utf8)
+{
+        char *tmp = strdup(uevent);
+        char *saveptr = NULL;
+        char *line;
+        char *key;
+        char *value;
+
+        int found_id = 0;
+        int found_serial = 0;
+        int found_name = 0;
+
+        line = strtok_r(tmp, "\n", &saveptr);
+        while (line != NULL) {
+                /* line: "KEY=value" */
+                key = line;
+                value = strchr(line, '=');
+                if (!value) {
+                        goto next_line;
+                }
+                *value = '\0';
+                value++;
+
+                if (strcmp(key, "HID_ID") == 0) {
+                        /**
+                         *        type vendor   product
+                         * HID_ID=0003:000005AC:00008242
+                         **/
+                        int ret = sscanf(value, "%x:%hx:%hx", bus_type, vendor_id, product_id);
+                        if (ret == 3) {
+                                found_id = 1;
+                        }
+                } else if (strcmp(key, "HID_NAME") == 0) {
+                        /* The caller has to free the product name */
+                        *product_name_utf8 = strdup(value);
+                        found_name = 1;
+                } else if (strcmp(key, "HID_UNIQ") == 0) {
+                        /* The caller has to free the serial number */
+                        *serial_number_utf8 = strdup(value);
+                        found_serial = 1;
+                }
+
+next_line:
+                line = strtok_r(NULL, "\n", &saveptr);
+        }
+
+        free(tmp);
+        return (found_id && found_name && found_serial);
+}
+
+
+static int get_device_string(hid_device *dev, enum device_string_id key, wchar_t *string, size_t maxlen)
+{
+        struct udev *udev;
+        struct udev_device *udev_dev, *parent, *hid_dev;
+        struct stat s;
+        int ret = -1;
+        char *serial_number_utf8 = NULL;
+        char *product_name_utf8 = NULL;
+
+        /* Create the udev object */
+        udev = udev_new();
+        if (!udev) {
+                printf("Can't create udev\n");
+                return -1;
+        }
+
+        /* Get the dev_t (major/minor numbers) from the file handle. */
+        fstat(dev->device_handle, &s);
+        /* Open a udev device from the dev_t. 'c' means character device. */
+        udev_dev = udev_device_new_from_devnum(udev, 'c', s.st_rdev);
+        if (udev_dev) {
+                hid_dev = udev_device_get_parent_with_subsystem_devtype(
+                        udev_dev,
+                        "hid",
+                        NULL);
+                if (hid_dev) {
+                        unsigned short dev_vid;
+                        unsigned short dev_pid;
+                        int bus_type;
+                        size_t retm;
+
+                        ret = parse_uevent_info(
+                                   udev_device_get_sysattr_value(hid_dev, "uevent"),
+                                   &bus_type,
+                                   &dev_vid,
+                                   &dev_pid,
+                                   &serial_number_utf8,
+                                   &product_name_utf8);
+
+                        if (bus_type == BUS_BLUETOOTH) {
+                                switch (key) {
+                                        case DEVICE_STRING_MANUFACTURER:
+                                                wcsncpy(string, L"", maxlen);
+                                                ret = 0;
+                                                break;
+                                        case DEVICE_STRING_PRODUCT:
+                                                retm = mbstowcs(string, product_name_utf8, maxlen);
+                                                ret = (retm == (size_t)-1)? -1: 0;
+                                                break;
+                                        case DEVICE_STRING_SERIAL:
+                                                retm = mbstowcs(string, serial_number_utf8, maxlen);
+                                                ret = (retm == (size_t)-1)? -1: 0;
+                                                break;
+                                        case DEVICE_STRING_COUNT:
+                                        default:
+                                                ret = -1;
+                                                break;
+                                }
+                        }
+                        else {
+                                /* This is a USB device. Find its parent USB Device node. */
+                                parent = udev_device_get_parent_with_subsystem_devtype(
+                                           udev_dev,
+                                           "usb",
+                                           "usb_device");
+                                if (parent) {
+                                        const char *str;
+                                        const char *key_str = NULL;
+
+                                        if (key < DEVICE_STRING_COUNT) {
+                                                key_str = device_string_names[key];
+                                        } else {
+                                                ret = -1;
+                                                goto end;
+                                        }
+
+                                        str = udev_device_get_sysattr_value(parent, key_str);
+                                        if (str) {
+                                                /* Convert the string from UTF-8 to wchar_t */
+                                                retm = mbstowcs(string, str, maxlen);
+                                                ret = (retm == (size_t)-1)? -1: 0;
+                                                goto end;
+                                        }
+                                }
+                        }
+                }
+        }
+
+end:
+        free(serial_number_utf8);
+        free(product_name_utf8);
+
+        udev_device_unref(udev_dev);
+        /* parent and hid_dev don't need to be (and can't be) unref'd.
+           I'm not sure why, but they'll throw double-free() errors. */
+        udev_unref(udev);
+
+        return ret;
+}
+
+int HID_API_EXPORT hid_init(void)
+{
+        const char *locale;
+
+        /* Set the locale if it's not set. */
+        locale = setlocale(LC_CTYPE, NULL);
+        if (!locale)
+                setlocale(LC_CTYPE, "");
+
+        return 0;
+}
+
+int HID_API_EXPORT hid_exit(void)
+{
+        /* Nothing to do for this in the Linux/hidraw implementation. */
+        return 0;
+}
+
+
+struct hid_device_info  HID_API_EXPORT *hid_enumerate(unsigned short vendor_id, unsigned short product_id)
+{
+        struct udev *udev;
+        struct udev_enumerate *enumerate;
+        struct udev_list_entry *devices, *dev_list_entry;
+
+        struct hid_device_info *root = NULL; /* return object */
+        struct hid_device_info *cur_dev = NULL;
+        struct hid_device_info *prev_dev = NULL; /* previous device */
+
+        hid_init();
+
+        /* Create the udev object */
+        udev = udev_new();
+        if (!udev) {
+                printf("Can't create udev\n");
+                return NULL;
+        }
+
+        /* Create a list of the devices in the 'hidraw' subsystem. */
+        enumerate = udev_enumerate_new(udev);
+        udev_enumerate_add_match_subsystem(enumerate, "hidraw");
+        udev_enumerate_scan_devices(enumerate);
+        devices = udev_enumerate_get_list_entry(enumerate);
+        /* For each item, see if it matches the vid/pid, and if so
+           create a udev_device record for it */
+        udev_list_entry_foreach(dev_list_entry, devices) {
+                const char *sysfs_path;
+                const char *dev_path;
+                const char *str;
+                struct udev_device *raw_dev; /* The device's hidraw udev node. */
+                struct udev_device *hid_dev; /* The device's HID udev node. */
+                struct udev_device *usb_dev; /* The device's USB udev node. */
+                struct udev_device *intf_dev; /* The device's interface (in the USB sense). */
+                unsigned short dev_vid;
+                unsigned short dev_pid;
+                char *serial_number_utf8 = NULL;
+                char *product_name_utf8 = NULL;
+                int bus_type;
+                int result;
+
+                /* Get the filename of the /sys entry for the device
+                   and create a udev_device object (dev) representing it */
+                sysfs_path = udev_list_entry_get_name(dev_list_entry);
+                raw_dev = udev_device_new_from_syspath(udev, sysfs_path);
+                dev_path = udev_device_get_devnode(raw_dev);
+
+                hid_dev = udev_device_get_parent_with_subsystem_devtype(
+                        raw_dev,
+                        "hid",
+                        NULL);
+
+                if (!hid_dev) {
+                        /* Unable to find parent hid device. */
+                        goto next;
+                }
+
+                result = parse_uevent_info(
+                        udev_device_get_sysattr_value(hid_dev, "uevent"),
+                        &bus_type,
+                        &dev_vid,
+                        &dev_pid,
+                        &serial_number_utf8,
+                        &product_name_utf8);
+
+                if (!result) {
+                        /* parse_uevent_info() failed for at least one field. */
+                        goto next;
+                }
+
+                if (bus_type != BUS_USB && bus_type != BUS_BLUETOOTH) {
+                        /* We only know how to handle USB and BT devices. */
+                        goto next;
+                }
+
+                /* Check the VID/PID against the arguments */
+                if ((vendor_id == 0x0 || vendor_id == dev_vid) &&
+                    (product_id == 0x0 || product_id == dev_pid)) {
+                        struct hid_device_info *tmp;
+
+                        /* VID/PID match. Create the record. */
+                        tmp = malloc(sizeof(struct hid_device_info));
+                        if (cur_dev) {
+                                cur_dev->next = tmp;
+                        }
+                        else {
+                                root = tmp;
+                        }
+                        prev_dev = cur_dev;
+                        cur_dev = tmp;
+
+                        /* Fill out the record */
+                        cur_dev->next = NULL;
+                        cur_dev->path = dev_path? strdup(dev_path): NULL;
+
+                        /* VID/PID */
+                        cur_dev->vendor_id = dev_vid;
+                        cur_dev->product_id = dev_pid;
+
+                        /* Serial Number */
+                        cur_dev->serial_number = utf8_to_wchar_t(serial_number_utf8);
+
+                        /* Release Number */
+                        cur_dev->release_number = 0x0;
+
+                        /* Interface Number */
+                        cur_dev->interface_number = -1;
+
+                        switch (bus_type) {
+                                case BUS_USB:
+                                        /* The device pointed to by raw_dev contains information about
+                                           the hidraw device. In order to get information about the
+                                           USB device, get the parent device with the
+                                           subsystem/devtype pair of "usb"/"usb_device". This will
+                                           be several levels up the tree, but the function will find
+                                           it. */
+                                        usb_dev = udev_device_get_parent_with_subsystem_devtype(
+                                                        raw_dev,
+                                                        "usb",
+                                                        "usb_device");
+
+                                        if (!usb_dev) {
+                                                /* Free this device */
+                                                free(cur_dev->serial_number);
+                                                free(cur_dev->path);
+                                                free(cur_dev);
+
+                                                /* Take it off the device list. */
+                                                if (prev_dev) {
+                                                        prev_dev->next = NULL;
+                                                        cur_dev = prev_dev;
+                                                }
+                                                else {
+                                                        cur_dev = root = NULL;
+                                                }
+
+                                                goto next;
+                                        }
+
+                                        /* Manufacturer and Product strings */
+                                        cur_dev->manufacturer_string = copy_udev_string(usb_dev, device_string_names[DEVICE_STRING_MANUFACTURER]);
+                                        cur_dev->product_string = copy_udev_string(usb_dev, device_string_names[DEVICE_STRING_PRODUCT]);
+
+                                        /* Release Number */
+                                        str = udev_device_get_sysattr_value(usb_dev, "bcdDevice");
+                                        cur_dev->release_number = (str)? strtol(str, NULL, 16): 0x0;
+
+                                        /* Get a handle to the interface's udev node. */
+                                        intf_dev = udev_device_get_parent_with_subsystem_devtype(
+                                                        raw_dev,
+                                                        "usb",
+                                                        "usb_interface");
+                                        if (intf_dev) {
+                                                str = udev_device_get_sysattr_value(intf_dev, "bInterfaceNumber");
+                                                cur_dev->interface_number = (str)? strtol(str, NULL, 16): -1;
+                                        }
+
+                                        break;
+
+                                case BUS_BLUETOOTH:
+                                        /* Manufacturer and Product strings */
+                                        cur_dev->manufacturer_string = wcsdup(L"");
+                                        cur_dev->product_string = utf8_to_wchar_t(product_name_utf8);
+
+                                        break;
+
+                                default:
+                                        /* Unknown device type - this should never happen, as we
+                                         * check for USB and Bluetooth devices above */
+                                        break;
+                        }
+                }
+
+        next:
+                free(serial_number_utf8);
+                free(product_name_utf8);
+                udev_device_unref(raw_dev);
+                /* hid_dev, usb_dev and intf_dev don't need to be (and can't be)
+                   unref()d.  It will cause a double-free() error.  I'm not
+                   sure why.  */
+        }
+        /* Free the enumerator and udev objects. */
+        udev_enumerate_unref(enumerate);
+        udev_unref(udev);
+
+        return root;
+}
+
+void  HID_API_EXPORT hid_free_enumeration(struct hid_device_info *devs)
+{
+        struct hid_device_info *d = devs;
+        while (d) {
+                struct hid_device_info *next = d->next;
+                free(d->path);
+                free(d->serial_number);
+                free(d->manufacturer_string);
+                free(d->product_string);
+                free(d);
+                d = next;
+        }
+}
+
+hid_device * hid_open(unsigned short vendor_id, unsigned short product_id, const wchar_t *serial_number)
+{
+        struct hid_device_info *devs, *cur_dev;
+        const char *path_to_open = NULL;
+        hid_device *handle = NULL;
+
+        devs = hid_enumerate(vendor_id, product_id);
+        cur_dev = devs;
+        while (cur_dev) {
+                if (cur_dev->vendor_id == vendor_id &&
+                    cur_dev->product_id == product_id) {
+                        if (serial_number) {
+                                if (wcscmp(serial_number, cur_dev->serial_number) == 0) {
+                                        path_to_open = cur_dev->path;
+                                        break;
+                                }
+                        }
+                        else {
+                                path_to_open = cur_dev->path;
+                                break;
+                        }
+                }
+                cur_dev = cur_dev->next;
+        }
+
+        if (path_to_open) {
+                /* Open the device */
+                handle = hid_open_path(path_to_open);
+        }
+
+        hid_free_enumeration(devs);
+
+        return handle;
+}
+
+hid_device * HID_API_EXPORT hid_open_path(const char *path)
+{
+        hid_device *dev = NULL;
+
+        hid_init();
+
+        dev = new_hid_device();
+
+        if (kernel_version == 0) {
+                struct utsname name;
+                int major, minor, release;
+                int ret;
+                uname(&name);
+                ret = sscanf(name.release, "%d.%d.%d", &major, &minor, &release);
+                if (ret == 3) {
+                        kernel_version = major << 16 | minor << 8 | release;
+                        //printf("Kernel Version: %d\n", kernel_version);
+                }
+                else {
+                        printf("Couldn't sscanf() version string %s\n", name.release);
+                }
+        }
+
+        /* OPEN HERE */
+        dev->device_handle = open(path, O_RDWR);
+
+        /* If we have a good handle, return it. */
+        if (dev->device_handle > 0) {
+
+                /* Get the report descriptor */
+                int res, desc_size = 0;
+                struct hidraw_report_descriptor rpt_desc;
+
+                memset(&rpt_desc, 0x0, sizeof(rpt_desc));
+
+                /* Get Report Descriptor Size */
+                res = ioctl(dev->device_handle, HIDIOCGRDESCSIZE, &desc_size);
+                if (res < 0)
+                        perror("HIDIOCGRDESCSIZE");
+
+
+                /* Get Report Descriptor */
+                rpt_desc.size = desc_size;
+                res = ioctl(dev->device_handle, HIDIOCGRDESC, &rpt_desc);
+                if (res < 0) {
+                        perror("HIDIOCGRDESC");
+                } else {
+                        /* Determine if this device uses numbered reports. */
+                        dev->uses_numbered_reports =
+                                uses_numbered_reports(rpt_desc.value,
+                                                      rpt_desc.size);
+                }
+
+                return dev;
+        }
+        else {
+                /* Unable to open any devices. */
+                free(dev);
+                return NULL;
+        }
+}
+
+
+int HID_API_EXPORT hid_write(hid_device *dev, const unsigned char *data, size_t length)
+{
+        int bytes_written;
+
+        bytes_written = write(dev->device_handle, data, length);
+
+        return bytes_written;
+}
+
+
+int HID_API_EXPORT hid_read_timeout(hid_device *dev, unsigned char *data, size_t length, int milliseconds)
+{
+        int bytes_read;
+
+        if (milliseconds >= 0) {
+                /* Milliseconds is either 0 (non-blocking) or > 0 (contains
+                   a valid timeout). In both cases we want to call poll()
+                   and wait for data to arrive.  Don't rely on non-blocking
+                   operation (O_NONBLOCK) since some kernels don't seem to
+                   properly report device disconnection through read() when
+                   in non-blocking mode.  */
+                int ret;
+                struct pollfd fds;
+
+                fds.fd = dev->device_handle;
+                fds.events = POLLIN;
+                fds.revents = 0;
+                ret = poll(&fds, 1, milliseconds);
+                if (ret == -1 || ret == 0) {
+                        /* Error or timeout */
+                        return ret;
+                }
+                else {
+                        /* Check for errors on the file descriptor. This will
+                           indicate a device disconnection. */
+                        if (fds.revents & (POLLERR | POLLHUP | POLLNVAL))
+                                return -1;
+                }
+        }
+
+        bytes_read = read(dev->device_handle, data, length);
+        if (bytes_read < 0 && (errno == EAGAIN || errno == EINPROGRESS))
+                bytes_read = 0;
+
+        if (bytes_read >= 0 &&
+            kernel_version < KERNEL_VERSION(2,6,34) &&
+            dev->uses_numbered_reports) {
+                /* Work around a kernel bug. Chop off the first byte. */
+                memmove(data, data+1, bytes_read);
+                bytes_read--;
+        }
+
+        return bytes_read;
+}
+
+int HID_API_EXPORT hid_read(hid_device *dev, unsigned char *data, size_t length)
+{
+        return hid_read_timeout(dev, data, length, (dev->blocking)? -1: 0);
+}
+
+int HID_API_EXPORT hid_set_nonblocking(hid_device *dev, int nonblock)
+{
+        /* Do all non-blocking in userspace using poll(), since it looks
+           like there's a bug in the kernel in some versions where
+           read() will not return -1 on disconnection of the USB device */
+
+        dev->blocking = !nonblock;
+        return 0; /* Success */
+}
+
+
+int HID_API_EXPORT hid_send_feature_report(hid_device *dev, const unsigned char *data, size_t length)
+{
+        int res;
+
+        res = ioctl(dev->device_handle, HIDIOCSFEATURE(length), data);
+        if (res < 0)
+                perror("ioctl (SFEATURE)");
+
+        return res;
+}
+
+int HID_API_EXPORT hid_get_feature_report(hid_device *dev, unsigned char *data, size_t length)
+{
+        int res;
+
+        res = ioctl(dev->device_handle, HIDIOCGFEATURE(length), data);
+        if (res < 0)
+                perror("ioctl (GFEATURE)");
+
+
+        return res;
+}
+
+
+void HID_API_EXPORT hid_close(hid_device *dev)
+{
+        if (!dev)
+                return;
+        close(dev->device_handle);
+        free(dev);
+}
+
+
+int HID_API_EXPORT_CALL hid_get_manufacturer_string(hid_device *dev, wchar_t *string, size_t maxlen)
+{
+        return get_device_string(dev, DEVICE_STRING_MANUFACTURER, string, maxlen);
+}
+
+int HID_API_EXPORT_CALL hid_get_product_string(hid_device *dev, wchar_t *string, size_t maxlen)
+{
+        return get_device_string(dev, DEVICE_STRING_PRODUCT, string, maxlen);
+}
+
+int HID_API_EXPORT_CALL hid_get_serial_number_string(hid_device *dev, wchar_t *string, size_t maxlen)
+{
+        return get_device_string(dev, DEVICE_STRING_SERIAL, string, maxlen);
+}
+
+int HID_API_EXPORT_CALL hid_get_indexed_string(hid_device *dev, int string_index, wchar_t *string, size_t maxlen)
+{
+        return -1;
+}
+
+
+HID_API_EXPORT const wchar_t * HID_API_CALL  hid_error(hid_device *dev)
+{
+        return NULL;
+}