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100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
/* Simple example of how to use libuEv with Linux joystick API
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*
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* Copyright (c) 2014-2024 Joachim Wiberg <troglobit()gmail!com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <err.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include "uev.h"
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struct js_event {
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uint32_t time; /* event timestamp in milliseconds */
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int16_t value; /* value */
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uint8_t type; /* event type */
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uint8_t number; /* axis/button number */
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} e;
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/*
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* Always check for UEV_ERROR in watcher callback!
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* Possibly joystick was unplugged
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*/
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static void joystick_cb(uev_t *w, void *arg, int events)
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{
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ssize_t len;
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if (UEV_ERROR == events) {
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warnx("Spurious problem with the joystick watcher, restarting.");
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uev_io_start(w);
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}
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len = read(w->fd, &e, sizeof(e));
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if (len < 0) {
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warn("Failed reading joystick event");
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return;
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}
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if (len == 0 || UEV_HUP == events) {
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warn("Joystick disconnected");
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return;
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}
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switch (e.type) {
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case 1:
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printf("Button %d %s\n", e.number, e.value ? "pressed" : "released");
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break;
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case 2:
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printf("Joystick axis %d moved, value %d!\n", e.number, e.value);
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break;
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}
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}
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int main(void)
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{
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uev_ctx_t ctx;
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uev_t js1;
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int fd;
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fd = open("/dev/input/js0", O_RDONLY, O_NONBLOCK);
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if (fd < 0)
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errx(errno, "Cannot find a joystick attached.");
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uev_init(&ctx);
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uev_io_init(&ctx, &js1, joystick_cb, NULL, fd, UEV_READ);
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puts("Starting, press Ctrl-C to exit.");
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return uev_run(&ctx, 0);
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}
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/**
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* Local Variables:
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* compile-command: "make joystick"
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* indent-tabs-mode: t
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* c-file-style: "linux"
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* End:
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*/
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