#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <sys/ioctl.h> #include <sys/time.h> #include <linux/soundcard.h> #define DEVICE "/dev/sequencer" int main(int argc, char *argv[]) { int fd; ssize_t res; unsigned char ev[4]; fd = open(DEVICE, O_RDWR); if (fd < 0) { perror( "open (" DEVICE ")" ); return EXIT_FAILURE; } ev[0] = SEQ_MIDIPUTC; ev[1] = 0xfe; /* active sensing */ ev[2] = argc > 1 ? atoi(argv[1]) : 0; res = write(fd, &ev, sizeof(ev)); printf("end res = %li\n", (long)res); close(fd); return EXIT_SUCCESS; }