commit eef7c77ee24fec31665ac9eb00a7ad68889d02ef
Author: David DiPaola <DavidDiPaola@users.noreply.github.com>
Date: Wed, 17 Oct 2018 18:58:25 -0400
initial commit
Diffstat:
| A | .gitignore | | | 3 | +++ |
| A | Makefile | | | 15 | +++++++++++++++ |
| A | main.c | | | 73 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
3 files changed, 91 insertions(+), 0 deletions(-)
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,3 @@
+*.o
+linux_joystick_helloworld
+
diff --git a/Makefile b/Makefile
@@ -0,0 +1,15 @@
+BIN = linux_joystick_helloworld
+
+_CFLAGS = -Wall -Wextra \
+ $(CFLAGS)
+
+.PHONY: all
+all: $(BIN)
+
+$(BIN): main.c
+ $(CC) $(_CFLAGS) $< -o $@
+
+.PHONY: clean
+clean:
+ rm -rf $(BIN)
+
diff --git a/main.c b/main.c
@@ -0,0 +1,73 @@
+#include <stdio.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#include <unistd.h>
+
+#include <errno.h>
+
+#include <linux/joystick.h>
+
+int
+main() {
+ printf("open() ..." "\n");
+ int js_fd = -1;
+ char js_path[64];
+ #define js_path_BASE "/dev/input/js"
+ for (int i=0; (i<=9 && js_fd<0); i++) {
+ snprintf(js_path, sizeof(js_path), js_path_BASE "%i", i);
+ js_fd = open(js_path, O_RDONLY | O_NONBLOCK);
+ }
+ if (js_fd < 0) {
+ fprintf(stderr, "ERROR: could not open any joystick devices at " js_path_BASE "X" "\n");
+ return 1;
+ }
+ printf("open() success (%s)" "\n", js_path);
+ #undef js_path_BASE
+
+ printf("ioctl() %s :" "\n", js_path);
+ char c;
+ ioctl(js_fd, JSIOCGAXES, &c); printf("\t" "number of axes: %i" "\n", c);
+ ioctl(js_fd, JSIOCGBUTTONS, &c); printf("\t" "number of buttons: %i" "\n", c);
+ char s[128] = "Unknown";
+ ioctl(js_fd, JSIOCGNAME(sizeof(s)), s); printf("\t" "name: %s" "\n", s);
+
+ printf("press HOME button to exit" "\n");
+ int done = 0;
+ while (!done) {
+ usleep(16666);
+
+ struct js_event event;
+ ssize_t amount = read(js_fd, &event, sizeof(event));
+ if (amount < (ssize_t)sizeof(event)) {
+ if (errno != EAGAIN) {
+ fprintf(stderr, "%s: read() expected %zi bytes but got %zi bytes" "\n", js_path, amount, sizeof(event));
+ return 1;
+ }
+ else {
+ continue;
+ }
+ }
+
+ if (event.type & JS_EVENT_AXIS) {
+ printf("axis %i = %i" "\n", event.number, event.value);
+ }
+ else if (event.type & JS_EVENT_BUTTON) {
+ printf("button %i = %i" "\n", event.number, event.value);
+ if ((event.number == 8) && event.value) {
+ done = 1;
+ }
+ }
+ else if (event.type & JS_EVENT_INIT) {
+ printf("init" "\n");
+ }
+ else {
+ printf("WARNING: event type unknown (0x%02X)" "\n", event.type);
+ }
+ }
+
+ close(js_fd);
+}
+
