/* gcc -o setbaud.exe setbaud.c */

#include <termios.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>

long speedtol(speed_t code)
{
switch (code) {
    case B0:     return(0);
    case B300:   return(300);
    case B1200:  return(1200);
    case B2400:  return(2400);
    case B4800:  return(4800);
    case B9600:  return(9600);
    case B19200: return(19200);
    case B38400: return(38400);
    case B57600: return(57600);
     default: return(115200);
      }
}

speed_t ltospeed(long speed)
{
    if (speed < 300) 		return  B0;
    else if (speed < 1200)	return  B300;
    else if (speed < 2400)	return  B1200;
    else if (speed < 4800)	return  B2400;
    else if (speed < 9600)	return  B4800;
    else if (speed < 19200)	return  B9600;
    else if (speed < 38400)	return  B19200;
    else if (speed < 57600)	return  B38400;
    else if (speed < 115200)	return  B57600;
    else			return  B115200;
}
int main(int argc, char **argv)
{
	int fd;
	struct termios term_info;
	long baud;
	speed_t speed;
	baud = 0l;
	if (argc != 3)
	{
		printf("Usage: %s filespec baudrate\n"
			"e.g. %s /dev/com1 4800\n", argv[0], argv[0]);
		return(-1);
	}
	else
	{
		if ((fd = open(argv[1], O_RDWR)) < 0)
		{
			printf("Unable to open port %s\n", argv[1]);
			return(1);
		}
		if (tcgetattr(fd, &term_info) == -1)
		{
			printf("Unable to retrieve attributes of port %s\n", argv[1]);
			(void)close(fd);
			return(2);
		}
		baud = atol(argv[2]);
		speed = ltospeed(baud);
		printf("Setting speed to %ld\n...", baud);
		if (cfsetispeed(&term_info, speed))
		{
			printf("Unable to set desired input baud rate\n");
			(void)close(fd);
			return(3);
		}
		if (cfsetospeed(&term_info, speed))
		{
			printf("Unable to set desired output baud rate\n");
			(void)close(fd);
			return(4);
		}
		if (tcsetattr(fd, TCSANOW, &term_info))
		{
			printf("Unable to assign attributes\n");
			(void)close(fd);
			return(5);
		}
		printf("Speed for %s is now %ld out, %ld in.\n", 
			argv[1],
		       	speedtol(cfgetospeed(&term_info)),
		       	speedtol(cfgetispeed(&term_info)));
		(void)close(fd);
		return(0);
	}
}