path: root/hidapi.h

/*******************************************************
 HIDAPI - Multi-Platform library for
 communication with HID devices.

 Alan Ott
 Signal 11 Software

 8/22/2009

 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 .
********************************************************/

/** @file
 * @defgroup API hidapi API
 */

#ifndef HIDAPI_H__
#define HIDAPI_H__

#include <wchar.h>

#ifdef _WIN32
      #define HID_API_EXPORT __declspec(dllexport)
      #define HID_API_CALL
#else
      #define HID_API_EXPORT /**< API export macro */
      #define HID_API_CALL /**< API call macro */
#endif

#define HID_API_EXPORT_CALL HID_API_EXPORT HID_API_CALL /**< API export and call macro*/

#ifdef __cplusplus
extern "C" {
#endif
        struct hid_device_;
        typedef struct hid_device_ hid_device; /**< opaque hidapi structure */

        /** hidapi info structure */
        struct hid_device_info {
            /** Platform-specific device path */
            char *path;
            /** Device Vendor ID */
            unsigned short vendor_id;
            /** Device Product ID */
            unsigned short product_id;
            /** Serial Number */
            wchar_t *serial_number;
            /** Device Release Number in binary-coded decimal,
                also known as Device Version Number */
            unsigned short release_number;
            /** Manufacturer String */
            wchar_t *manufacturer_string;
            /** Product string */
            wchar_t *product_string;
            /** Usage Page for this Device/Interface
                (Windows/Mac only). */
            unsigned short usage_page;
            /** Usage for this Device/Interface
                (Windows/Mac only).*/
            unsigned short usage;
            /** The USB interface which this logical device
                represents (Linux/libusb implementation only). */
            int interface_number;

            /** Pointer to the next device */
            struct hid_device_info *next;
        };


        /** @brief Enumerate the HID Devices.

            This function returns a linked list of all the HID devices
            attached to the system which match vendor_id and product_id.
            If @p vendor_id and @p product_id are both set to 0, then
            all HID devices will be returned.

            @ingroup API
            @param vendor_id The Vendor ID (VID) of the types of device
                to open.
            @param product_id The Product ID (PID) of the types of
                device to open.

            @returns
                This function returns a pointer to a linked list of type
                struct #hid_device, containing information about the HID devices
                attached to the system, or NULL in the case of failure. Free
                this linked list by calling hid_free_enumeration().
        */
        struct hid_device_info HID_API_EXPORT * HID_API_CALL hid_enumerate(unsigned short vendor_id, unsigned short product_id);

        /** @brief Free an enumeration Linked List

            This function frees a linked list created by hid_enumerate().

            @ingroup API
            @param devs Pointer to a list of struct_device returned from
                      hid_enumerate().
        */
        void  HID_API_EXPORT HID_API_CALL hid_free_enumeration(struct hid_device_info *devs);

        /** @brief Open a HID device using a Vendor ID (VID), Product ID
            (PID) and optionally a serial number.

            If @p serial_number is NULL, the first device with the
            specified VID and PID is opened.

            @ingroup API
            @param vendor_id The Vendor ID (VID) of the device to open.
            @param product_id The Product ID (PID) of the device to open.
            @param serial_number The Serial Number of the device to open
                               (Optionally NULL).

            @returns
                This function returns a pointer to a #hid_device object on
                success or NULL on failure.
        */
        HID_API_EXPORT hid_device * HID_API_CALL hid_open(unsigned short vendor_id, unsigned short product_id, wchar_t *serial_number);

        /** @brief Open a HID device by its path name.

            The path name be determined by calling hid_enumerate(), or a
            platform-specific path name can be used (eg: /dev/hidraw0 on
            Linux).

            @ingroup API
            @param path The path name of the device to open

            @returns
                This function returns a pointer to a #hid_device object on
                success or NULL on failure.
        */
        HID_API_EXPORT hid_device * HID_API_CALL hid_open_path(const char *path);

        /** @brief Write an Output report to a HID device.

            The first byte of @p data[] must contain the Report ID. For
            devices which only support a single report, this must be set
            to 0x0. The remaining bytes contain the report data. Since
            the Report ID is mandatory, calls to hid_write() will always
            contain one more byte than the report contains. For example,
            if a hid report is 16 bytes long, 17 bytes must be passed to
            hid_write(), the Report ID (or 0x0, for devices with a
            single report), followed by the report data (16 bytes). In
            this example, the length passed in would be 17.

            hid_write() will send the data on the first OUT endpoint, if
            one exists. If it does not, it will send the data through
            the Control Endpoint (Endpoint 0).

            @ingroup API
            @param device A device handle returned from hid_open().
            @param data The data to send, including the report number as
                the first byte.
            @param length The length in bytes of the data to send.

            @returns
                This function returns the actual number of bytes written and
                -1 on error.
        */
        int  HID_API_EXPORT HID_API_CALL hid_write(hid_device *device, const unsigned char *data, size_t length);

        /** @brief Read an Input report from a HID device.

            Input reports are returned
            to the host through the INTERRUPT IN endpoint. The first byte will
            contain the Report number if the device uses numbered reports.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param data A buffer to put the read data into.
            @param length The number of bytes to read. For devices with
                multiple reports, make sure to read an extra byte for
                the report number.

            @returns
                This function returns the actual number of bytes read and
                -1 on error.
        */
        int  HID_API_EXPORT HID_API_CALL hid_read(hid_device *device, unsigned char *data, size_t length);

        /** @brief Set the device handle to be non-blocking.

            In non-blocking mode calls to hid_read() will return
            immediately with a value of 0 if there is no data to be
            read. In blocking mode, hid_read() will wait (block) until
            there is data to read before returning.

            Nonblocking can be turned on and off at any time.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param nonblock enable or not the nonblocking reads
             - 1 to enable nonblocking
             - 0 to disable nonblocking.

            @returns
                This function returns 0 on success and -1 on error.
        */
        int  HID_API_EXPORT HID_API_CALL hid_set_nonblocking(hid_device *device, int nonblock);

        /** @brief Send a Feature report to the device.

            Feature reports are sent over the Control endpoint as a
            Set_Report transfer.  The first byte of @p data[] must
            contain the Report ID. For devices which only support a
            single report, this must be set to 0x0. The remaining bytes
            contain the report data. Since the Report ID is mandatory,
            calls to hid_send_feature_report() will always contain one
            more byte than the report contains. For example, if a hid
            report is 16 bytes long, 17 bytes must be passed to
            hid_send_feature_report(): the Report ID (or 0x0, for
            devices which do not use numbered reports), followed by the
            report data (16 bytes). In this example, the length passed
            in would be 17.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param data The data to send, including the report number as
                the first byte.
            @param length The length in bytes of the data to send, including
                the report number.

            @returns
                This function returns the actual number of bytes written and
                -1 on error.
        */
        int HID_API_EXPORT HID_API_CALL hid_send_feature_report(hid_device *device, const unsigned char *data, size_t length);

        /** @brief Get a feature report from a HID device.

            Make sure to set the first byte of @p data[] to the Report
            ID of the report to be read.  Make sure to allow space for
            this extra byte in @p data[].

            @ingroup API
            @param device A device handle returned from hid_open().
            @param data A buffer to put the read data into, including
                the Report ID. Set the first byte of @p data[] to the
                Report ID of the report to be read.
            @param length The number of bytes to read, including an
                extra byte for the report ID. The buffer can be longer
                than the actual report.

            @returns
                This function returns the number of bytes read and
                -1 on error.
        */
        int HID_API_EXPORT HID_API_CALL hid_get_feature_report(hid_device *device, unsigned char *data, size_t length);

        /** @brief Close a HID device.

            @ingroup API
            @param device A device handle returned from hid_open().
        */
        void HID_API_EXPORT HID_API_CALL hid_close(hid_device *device);

        /** @brief Get The Manufacturer String from a HID device.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param string A wide string buffer to put the data into.
            @param maxlen The length of the buffer in multiples of wchar_t.

            @returns
                This function returns 0 on success and -1 on error.
        */
        int HID_API_EXPORT_CALL hid_get_manufacturer_string(hid_device *device, wchar_t *string, size_t maxlen);

        /** @brief Get The Product String from a HID device.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param string A wide string buffer to put the data into.
            @param maxlen The length of the buffer in multiples of wchar_t.

            @returns
                This function returns 0 on success and -1 on error.
        */
        int HID_API_EXPORT_CALL hid_get_product_string(hid_device *device, wchar_t *string, size_t maxlen);

        /** @brief Get The Serial Number String from a HID device.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param string A wide string buffer to put the data into.
            @param maxlen The length of the buffer in multiples of wchar_t.

            @returns
                This function returns 0 on success and -1 on error.
        */
        int HID_API_EXPORT_CALL hid_get_serial_number_string(hid_device *device, wchar_t *string, size_t maxlen);

        /** @brief Get a string from a HID device, based on its string index.

            @ingroup API
            @param device A device handle returned from hid_open().
            @param string_index The index of the string to get.
            @param string A wide string buffer to put the data into.
            @param maxlen The length of the buffer in multiples of wchar_t.

            @returns
                This function returns 0 on success and -1 on error.
        */
        int HID_API_EXPORT_CALL hid_get_indexed_string(hid_device *device, int string_index, wchar_t *string, size_t maxlen);

        /** @brief Get a string describing the last error which occurred.

            @ingroup API
            @param device A device handle returned from hid_open().

            @returns
                This function returns a string containing the last error
                which occurred or NULL if none has occurred.
        */
        HID_API_EXPORT const wchar_t* HID_API_CALL hid_error(hid_device *device);

#ifdef __cplusplus
}
#endif

#endif