Hi,
> { /*Receive incoming serial data.*/
> STOP=FALSE;
> res = 0; /*eventually shows where buffer ends*/
> sleep(1);
> /*Force a wait to cause receive buffer to stabilize.*/
> while (STOP==FALSE) { /* loop for input */
>
> res = read(fd,buf,sizeof(buf)); /* returns after sizeof(buf) chars have been inputed or timeoutt */
>
>
> STOP=TRUE;
> }
> buf[res]=NULL; /* so we can printf... */
that looks suspect to me, I forget what the spec says NULL means in that
case, but I'd use '\0' or just 0 instead, but what you do may work. I
also suspect that if read reads sizeof(buf) bytes and then you set
buf[sizeof(buf)] = 0 you will possibly touch memory that isn't yours.
Trev
> /*That makes sure there is a null to form a strint.*/
> /*printf("%s\n", buf); */
> return;
> } /*Receive incoming serial data.*/
>
> The only thing I can adjust in the port setup is a
> variable that is either kept at 0 so it will time out if no
> characters are received at all or to, say, 1024 or whatever the
> buffer is defined as. This really doesn't effect the issue but
> if set to > 0, the timeout never happens until at least one
> character is received.
>
> Here is the initialization routine. Hardware flow
> control is not an option as the receiver does not recognize
> RTS/CTS.
>
> #include "headers.h"
> #include "defs.h"
> #include "externs.h"
>
>
> void portinit()
> {
> struct termios oldtio,newtio;
>
> fd = open(MODEMDEVICE, O_RDWR | O_NOCTTY );
>
> if (fd <0) {perror(MODEMDEVICE); exit(-1); }
>
> tcgetattr(fd,&oldtio); /* save current port settings */
>
> /*Clear everything about that port.*/
> bzero(&newtio, sizeof(newtio));
>
> newtio.c_cflag = BAUDRATE | CS8 | CLOCAL | CREAD;
>
> newtio.c_iflag = IGNPAR | ICRNL;
>
> newtio.c_oflag &= ~OPOST;
>
>
> /* set input mode (non-canonical, no echo,...) */
>
> newtio.c_lflag = 0;
>
> newtio.c_cc[VTIME] = 20; /* inter-character timer .1 seconds/tick */
> newtio.c_cc[VMIN] = 0; /*Blocks until VMIN chars or timeout.*/
>
>
> tcflush(fd, TCIFLUSH);
>
> tcsetattr(fd,TCSANOW,&newtio);
>
> return;
> }
>
> I have tried tcflush at the end of a receive with absolutely no
> effect on anything.
> Shane W writes:
> > Hmm, reading from the ttySx device should never give
> > duplicatedcharacters so it sounds like something is up with
> > your buffer. I wouldn't zero it out but just keep note of
> > the number of bytes read and when to stop. Also, after your
> > first read returns, don't sleep but rather call poll() on
> > the device which will return when there is data ready to be
> > read.
>
> Yes. It is like it is already ready to receive data too
> early.
>
> The hardware is a USB-based 8-port adaptor which behaves
> quite normally when using Kermit or other serial routines.
>
> Thanks.
>
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