Date: Tue, 8 Aug 2000 14:11:00 -0700 (PDT) From: r_chipi@yahoo.com To: freebsd-gnats-submit@FreeBSD.org Subject: ports/20490: Termios timeout parameters, VMIN, VTIME, dont work with Python. Message-ID: <20000808211100.6472837B765@hub.freebsd.org>
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>Number: 20490
>Category: ports
>Synopsis: Termios timeout parameters, VMIN, VTIME, dont work with Python.
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-ports
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Aug 08 14:20:00 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator: Ramiro Chipi
>Release: 4.1-RELEASE
>Organization:
>Environment:
FreeBSD rc-fbsd.ote.racal.com 4.1-RELEASE FreeBSD 4.1-RELEASE #0: Thu Jul 27 04:44:16 GMT 2000 root@usw4.freebsd.org:/usr/src/sys/compile/GENERIC i386
>Description:
When using VMIN = 0 and VTIME > 0 to control receiver timeout
in Python, it does not work as it should. For example, programming
VMIN = 0 and VTIME = 200 should make a read block for at least 20 seconds
or until a character is received, however, the read does not block and
returns immediately. When a similar routine is written in C it works
as it should.
>How-To-Repeat:
To reapeat write the following test code:
# This code does not work
import os
from TERMIOS import *
from tty import *
fd = os.open("/dev/cuaa1", os.O_RDWR)
attrs = tcgetattr(fd)
attrs[CFLAG] = CS8 | CLOCAL | CREAD
attrs[OFLAG] = attrs[OFLAG] & ~OPOST
attrs[LFLAG] = 0
attrs[CC][VMIN] = 0
attrs[CC][VTIME] = 200
tcsetattr(fd, TCSANOW, attrs)
print os.read(fd, 80)
/* the equivalent test in C works as it should */
#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <fcntl.h>
main()
{
struct termios term;
int fd, bytes;
char buf[80];
fd = open("/dev/cuaa1", O_RDWR);
if (fd < 0)
{
perror("open");
return 1;
}
tcgetattr(fd, &term);
term.c_cflag = CS8 | CREAD | CLOCAL;
term.c_oflag &= ~OPOST;
term.c_lflag = 0;
term.c_cc[VMIN] = 0;
term.c_cc[VTIME] = 200;
tcsetattr(fd, TCSANOW, &term);
bytes = read(fd, buf, 40);
buf[bytes] = 0;
puts(buf);
return 0;
}
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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