Data commit

Task/Keyboard-input-Keypress-check/C/keyboard-input-keypress-check.c

@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <termios.h>  /* general terminal interface: tcgetattr, tcsetattr, tcflush */
+#include <unistd.h>   /* synchronous I/O multiplexing: select, FD_CLR, FD_ISSET, FD_SET, FD_ZERO */
+#include <fcntl.h>
+
+void set_mode(int want_key)
+{
+	static struct termios old, new;
+	if (!want_key) {
+		tcsetattr(STDIN_FILENO, TCSANOW, &old);
+		return;
+	}
+
+	tcgetattr(STDIN_FILENO, &old);
+	new = old;
+	new.c_lflag &= ~(ICANON | ECHO);
+	tcsetattr(STDIN_FILENO, TCSANOW, &new);
+}
+
+int get_key()
+{
+	int c = 0;
+	struct timeval tv;
+	fd_set fs;
+	tv.tv_usec = tv.tv_sec = 0;
+
+	FD_ZERO(&fs);
+	FD_SET(STDIN_FILENO, &fs);
+	select(STDIN_FILENO + 1, &fs, 0, 0, &tv);
+
+	if (FD_ISSET(STDIN_FILENO, &fs)) {
+		c = getchar();
+		set_mode(0);
+	}
+	return c;
+}
+
+int main()
+{
+	int c;
+	while(1) {
+		set_mode(1);
+                /* force C library buffers to be written to kernel buffers,
+                   and flush pending input to avoid previously pressed keys */
+                fflush(stdout);
+		while (!(c = get_key())) usleep(10000);
+		printf("key %d\n", c);
+	}
+}