test.c

contains a basic example usage of the HIDAPI library.

/*******************************************************
 HIDAPI - Multi-Platform library for
 communication with HID devices.
 
 Alan Ott
 Signal 11 Software
 
 libusb/hidapi Team
 
 Copyright 2022.
 
 This contents of this file may be used by anyone
 for any reason without any conditions and may be
 used as a starting point for your own applications
 which use HIDAPI.
********************************************************/
 
#include <stdio.h>
#include <wchar.h>
#include <string.h>
#include <stdlib.h>
 
#include <hidapi.h>
 
// Headers needed for sleeping.
#ifdef _WIN32
        #include <windows.h>
#else
        #include <unistd.h>
#endif
 
// Fallback/example
#ifndef HID_API_MAKE_VERSION
#define HID_API_MAKE_VERSION(mj, mn, p) (((mj) << 24) | ((mn) << 8) | (p))
#endif
#ifndef HID_API_VERSION
#define HID_API_VERSION HID_API_MAKE_VERSION(HID_API_VERSION_MAJOR, HID_API_VERSION_MINOR, HID_API_VERSION_PATCH)
#endif
 
//
// Sample using platform-specific headers
#if defined(__APPLE__) && HID_API_VERSION >= HID_API_MAKE_VERSION(0, 12, 0)
#include <hidapi_darwin.h>
#endif
 
#if defined(_WIN32) && HID_API_VERSION >= HID_API_MAKE_VERSION(0, 12, 0)
#include <hidapi_winapi.h>
#endif
 
#if defined(USING_HIDAPI_LIBUSB) && HID_API_VERSION >= HID_API_MAKE_VERSION(0, 12, 0)
#include <hidapi_libusb.h>
#endif
//
 
const char *hid_bus_name(hid_bus_type bus_type) {
        static const char *const HidBusTypeName[] = {
                "Unknown",
                "USB",
                "Bluetooth",
                "I2C",
                "SPI",
        };
 
        if ((int)bus_type < 0)
                bus_type = HID_API_BUS_UNKNOWN;
        if ((int)bus_type >= (int)(sizeof(HidBusTypeName) / sizeof(HidBusTypeName[0])))
                bus_type = HID_API_BUS_UNKNOWN;
 
        return HidBusTypeName[bus_type];
}
 
void print_device(struct hid_device_info *cur_dev) {
        printf("Device Found\n  type: %04hx %04hx\n  path: %s\n  serial_number: %ls", cur_dev->vendor_id, cur_dev->product_id, cur_dev->path, cur_dev->serial_number);
        printf("\n");
        printf("  Manufacturer: %ls\n", cur_dev->manufacturer_string);
        printf("  Product:      %ls\n", cur_dev->product_string);
        printf("  Release:      %hx\n", cur_dev->release_number);
        printf("  Interface:    %d\n",  cur_dev->interface_number);
        printf("  Usage (page): 0x%hx (0x%hx)\n", cur_dev->usage, cur_dev->usage_page);
        printf("  Bus type: %u (%s)\n", (unsigned)cur_dev->bus_type, hid_bus_name(cur_dev->bus_type));
        printf("\n");
}
 
void print_hid_report_descriptor_from_device(hid_device *device) {
        unsigned char descriptor[HID_API_MAX_REPORT_DESCRIPTOR_SIZE];
        int res = 0;
 
        printf("  Report Descriptor: ");
        res = hid_get_report_descriptor(device, descriptor, sizeof(descriptor));
        if (res < 0) {
                printf("error getting: %ls", hid_error(device));
        }
        else {
                printf("(%d bytes)", res);
        }
        for (int i = 0; i < res; i++) {
                if (i % 10 == 0) {
                        printf("\n");
                }
                printf("0x%02x, ", descriptor[i]);
        }
        printf("\n");
}
 
void print_hid_report_descriptor_from_path(const char *path) {
        hid_device *device = hid_open_path(path);
        if (device) {
                print_hid_report_descriptor_from_device(device);
                hid_close(device);
        }
        else {
                printf("  Report Descriptor: Unable to open device by path\n");
        }
}
 
void print_devices(struct hid_device_info *cur_dev) {
        for (; cur_dev; cur_dev = cur_dev->next) {
                print_device(cur_dev);
        }
}
 
void print_devices_with_descriptor(struct hid_device_info *cur_dev) {
        for (; cur_dev; cur_dev = cur_dev->next) {
                print_device(cur_dev);
                print_hid_report_descriptor_from_path(cur_dev->path);
        }
}
 
int main(int argc, char* argv[])
{
        (void)argc;
        (void)argv;
 
        int res;
        unsigned char buf[256];
        #define MAX_STR 255
        wchar_t wstr[MAX_STR];
        hid_device *handle;
        int i;
 
        struct hid_device_info *devs;
 
        printf("hidapi test/example tool. Compiled with hidapi version %s, runtime version %s.\n", HID_API_VERSION_STR, hid_version_str());
        if (HID_API_VERSION == HID_API_MAKE_VERSION(hid_version()->major, hid_version()->minor, hid_version()->patch)) {
                printf("Compile-time version matches runtime version of hidapi.\n\n");
        }
        else {
                printf("Compile-time version is different than runtime version of hidapi.\n]n");
        }
 
        if (hid_init())
                return -1;
 
#if defined(__APPLE__) && HID_API_VERSION >= HID_API_MAKE_VERSION(0, 12, 0)
        // To work properly needs to be called before hid_open/hid_open_path after hid_init.
        // Best/recommended option - call it right after hid_init.
        hid_darwin_set_open_exclusive(0);
#endif
 
        devs = hid_enumerate(0x0, 0x0);
        print_devices_with_descriptor(devs);
        hid_free_enumeration(devs);
 
        // Set up the command buffer.
        memset(buf,0x00,sizeof(buf));
        buf[0] = 0x01;
        buf[1] = 0x81;
 
 
        // Open the device using the VID, PID,
        // and optionally the Serial number.
        handle = hid_open(0x4d8, 0x3f, NULL);
        if (!handle) {
                printf("unable to open device\n");
                hid_exit();
                return 1;
        }
 
        // Read the Manufacturer String
        wstr[0] = 0x0000;
        res = hid_get_manufacturer_string(handle, wstr, MAX_STR);
        if (res < 0)
                printf("Unable to read manufacturer string\n");
        printf("Manufacturer String: %ls\n", wstr);
 
        // Read the Product String
        wstr[0] = 0x0000;
        res = hid_get_product_string(handle, wstr, MAX_STR);
        if (res < 0)
                printf("Unable to read product string\n");
        printf("Product String: %ls\n", wstr);
 
        // Read the Serial Number String
        wstr[0] = 0x0000;
        res = hid_get_serial_number_string(handle, wstr, MAX_STR);
        if (res < 0)
                printf("Unable to read serial number string\n");
        printf("Serial Number String: (%d) %ls\n", wstr[0], wstr);
 
        print_hid_report_descriptor_from_device(handle);
 
        struct hid_device_info* info = hid_get_device_info(handle);
        if (info == NULL) {
                printf("Unable to get device info\n");
        } else {
                print_devices(info);
        }
 
        // Read Indexed String 1
        wstr[0] = 0x0000;
        res = hid_get_indexed_string(handle, 1, wstr, MAX_STR);
        if (res < 0)
                printf("Unable to read indexed string 1\n");
        printf("Indexed String 1: %ls\n", wstr);
 
        // Set the hid_read() function to be non-blocking.
        hid_set_nonblocking(handle, 1);
 
        // Try to read from the device. There should be no
        // data here, but execution should not block.
        res = hid_read(handle, buf, 17);
 
        // Send a Feature Report to the device
        buf[0] = 0x2;
        buf[1] = 0xa0;
        buf[2] = 0x0a;
        buf[3] = 0x00;
        buf[4] = 0x00;
        res = hid_send_feature_report(handle, buf, 17);
        if (res < 0) {
                printf("Unable to send a feature report.\n");
        }
 
        memset(buf,0,sizeof(buf));
 
        // Read a Feature Report from the device
        buf[0] = 0x2;
        res = hid_get_feature_report(handle, buf, sizeof(buf));
        if (res < 0) {
                printf("Unable to get a feature report: %ls\n", hid_error(handle));
        }
        else {
                // Print out the returned buffer.
                printf("Feature Report\n   ");
                for (i = 0; i < res; i++)
                        printf("%02x ", (unsigned int) buf[i]);
                printf("\n");
        }
 
        memset(buf,0,sizeof(buf));
 
        // Toggle LED (cmd 0x80). The first byte is the report number (0x1).
        buf[0] = 0x1;
        buf[1] = 0x80;
        res = hid_write(handle, buf, 17);
        if (res < 0) {
                printf("Unable to write(): %ls\n", hid_error(handle));
        }
 
 
        // Request state (cmd 0x81). The first byte is the report number (0x1).
        buf[0] = 0x1;
        buf[1] = 0x81;
        hid_write(handle, buf, 17);
        if (res < 0) {
                printf("Unable to write()/2: %ls\n", hid_error(handle));
        }
 
        // Read requested state. hid_read() has been set to be
        // non-blocking by the call to hid_set_nonblocking() above.
        // This loop demonstrates the non-blocking nature of hid_read().
        res = 0;
        i = 0;
        while (res == 0) {
                res = hid_read(handle, buf, sizeof(buf));
                if (res == 0) {
                        printf("waiting...\n");
                }
                if (res < 0) {
                        printf("Unable to read(): %ls\n", hid_error(handle));
                        break;
                }
 
                i++;
                if (i >= 10) { /* 10 tries by 500 ms - 5 seconds of waiting*/
                        printf("read() timeout\n");
                        break;
                }
 
#ifdef _WIN32
                Sleep(500);
#else
                usleep(500*1000);
#endif
        }
 
        if (res > 0) {
                printf("Data read:\n   ");
                // Print out the returned buffer.
                for (i = 0; i < res; i++)
                        printf("%02x ", (unsigned int) buf[i]);
                printf("\n");
        }
 
        hid_close(handle);
 
        /* Free static HIDAPI objects. */
        hid_exit();
 
#ifdef _WIN32
        system("pause");
#endif
 
        return 0;
}