Serial Port problems in linux

Serial Port problems in linux-general Linux technology-Linux technology and application information. For details, refer to the following section. [I = s] This post was last edited by lgcHR

Note: I am a newbie. I did not write the program myself. I just modified it a little.
First, paste my serial port program, and then explain the problem:

Receiver:
/******************* Head file define **************** *******/
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include "math. h"
# Define max_buffer_size 100/* define the max buffer */

/*************************************** ******************/
Int fd, s;
Int open_serial (int k)
{
If (k = 0)/* serial port */
{
Fd = open ("/dev/ttyS0", O_RDWR | O_NOCTTY );
Perror ("open/dev/ttyS0 ");
}
Else
{
Fd = open ("/dev/ttyS1", O_RDWR | O_NOCTTY );
Perror ("open/dev/ttyS1 ");
}
Printf ("% d \ n", fd );
If (fd =-1)
Return-1;
}

/*************************************** *****************************/
Int main (int argc, char * argv [])
{
Char hd [max_buffer_size];/* define the receive buffer */

Int flag_close, retv, I, ncount = 0;

Struct termios opt;

Int realdata = 0;

/*************************************** ****************************/

Open_serial (0);/* open the serial 1 */

/*************************************** ****************************/

Tcgetattr (fd, & opt );

Cfmakeraw (& opt );

/*************************************** **************************/

Cfsetispeed (& opt, B9600);/* bound rate is set 9600 */

Cfsetospeed (& opt, B9600 );

/*************************************** ****************************/

Tcsetattr (fd, TCSANOW, & opt );

Printf ("ready for processing ing data... \ n ");

Retv = read (fd, hd, 50);/* receive data is stored int the fd,
Retv is the receive bytes numbers */
If (retv =-1)
Perror ("error !!! ");/* Read status biaozhi judge */

/*************************************** ***************************/

Printf ("The data converted Ed is: \ n");/* output the converted ed data */

For (I = 0; I <50; I ++)
{
Printf ("% c", hd );
}
Printf ("\ n ");
Flag_close = close (fd );
If (flag_close =-1)
Printf ("Close the Device failure \ n ");
Return 0;
}


The following is the sender program.
# Include
# Include
# Include
# Include
# Include
# Include
# Include
# Include
/*************************************** ****/
Int fd;

Int flag_close;

Int open_serial (int k)
{
If (k = 0)
{
Fd = open ("/dev/ttyS0", O_RDWR | O_NOCTTY );
Perror ("open/dev/ttyS0 ");
}
Else
{
Fd = open ("/dev/ttyS1", O_RDWR | O_NOCTTY );
Perror ("open/dev/ttyS1 ");
}
If (fd =-1)
Return-1;
}

/*************************************** *****************************/
Int main (int argc, char * argv [])

{

Char sbuf [] = {"Serial_Port test! \ N "};

Int sfd, retv, I;

Struct termios opt;

Int length = sizeof (sbuf );

/*************************************** ****************************/

Open_serial (0 );

/*************************************** ****************************/

Printf ("ready for sending data... \ n ");

Tcgetattr (fd, & opt );

Cfmakeraw (& opt );

/*************************************** **************************/

Cfsetispeed (& opt, B9600 );

Cfsetospeed (& opt, B9600 );

/*************************************** ****************************/

Tcsetattr (fd, TCSANOW, & opt );

Retv = write (fd, sbuf, length );

If (retv =-1)
{
Perror ("write ");
}

Printf ("the char numbers sent is % d \ n", retv );
Flag_close = close (fd );
If (flag_close =-1)
Printf ("Close the Device failure \ n ");
Return 0;
}
After running the program, sending is normal, and receiving is garbled, I don't know what is going on. I watched it on the same terminal under a user. I don't know if this method is correct. Please give me expert guidance.