serial break detection

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <termios.h>
#include <signal.h>
__sighandler_t sighandle(int signum, __sighandler_t h) {
    //fprintf(stderr, "BREAK DETECTED\n");
    printf("break com received\n");
    signal(SIGINT, (__sighandler_t) sighandle);
    return SIG_IGN;
}

int
set_interface_attribs (int fd, int speed, int parity)
{
        struct termios tty;
        memset (&tty, 0, sizeof tty);
        if (tcgetattr (fd, &tty) != 0)
        {
                printf ("error %d from tcgetattr", errno);
                return -1;
        }

        cfsetospeed (&tty, speed);
        cfsetispeed (&tty, speed);

        tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8| BRKINT;     // 8-bit chars
        // disable IGNBRK for mismatched speed tests; otherwise receive break
        // as \000 chars
        tty.c_iflag &= ~IGNBRK;         // ignore break signal
        tty.c_lflag = 0;                // no signaling chars, no echo,
                                        // no canonical processing
        tty.c_oflag = 0;                // no remapping, no delays
        tty.c_cc[VMIN]  = 0;            // read doesn't block
        tty.c_cc[VTIME] = 5;            // 0.5 seconds read timeout

        tty.c_iflag &= ~(IXON | IXOFF | IXANY); // shut off xon/xoff ctrl

        tty.c_cflag |= (CLOCAL | CREAD);// ignore modem controls,
                                        // enable reading
        tty.c_cflag &= ~(PARENB | PARODD);      // shut off parity
        tty.c_cflag |= parity;
        tty.c_cflag &= ~CSTOPB;
        tty.c_cflag &= ~CRTSCTS;

        if (tcsetattr (fd, TCSANOW, &tty) != 0)
        {
                printf ("error %d from tcsetattr", errno);
                return -1;
        }
        return 0;
}

void
set_blocking (int fd, int should_block)
{
        struct termios tty;
        memset (&tty, 0, sizeof tty);
        if (tcgetattr (fd, &tty) != 0)
        {
                printf ("error %d from tggetattr", errno);
                return;
        }

        tty.c_cc[VMIN]  = should_block ? 1 : 0;
        tty.c_cc[VTIME] = 5;            // 0.5 seconds read timeout

        if (tcsetattr (fd, TCSANOW, &tty) != 0)
                printf ("error %d setting term attributes", errno);
}


void main(){

char portname[] = "/dev/ttyO1";

    signal(SIGINT, (__sighandler_t) sighandle);//abilitazione ricezione break

int fd = open (portname, O_RDWR | O_NOCTTY | O_SYNC);
int value=0;
if (fd < 0)
{
        printf ("error %d opening %s: %s", errno, portname, strerror (errno));
        return;
}else{
printf("init port\n");
}

value=set_interface_attribs (fd, B19200, 0);  // set speed to 115,200 bps, 8n1 (no parity)
if(value==0)    printf("port opened ok\n");
set_blocking (fd, 0);                // set no blocking
printf("port no blocking ok\n");
write (fd, "hello!\n", 7);           // send 7 character greeting
char buf [100];
int n = 0;
int esci=0;
int i=0;
while(esci==0){
n=read (fd, buf, sizeof buf);  // read up to 100 characters if ready to read
for(i=0;i<n;i++){
printf("%c",buf[i]);
if(buf[i]=='*')
esci=1;
}
}
printf("\n");
close(fd);
}