From owner-freebsd-hackers  Tue Dec 19  9: 1:16 2000
From owner-freebsd-hackers@FreeBSD.ORG  Tue Dec 19 09:01:14 2000
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from exchange.universe.dart.spb (bb.marketsite.ru [194.226.198.1])
	by hub.freebsd.org (Postfix) with ESMTP id E8C1B37B402
	for <freebsd-hackers@freebsd.org>; Tue, 19 Dec 2000 09:01:11 -0800 (PST)
Received: from runnet-gw.marketsite.ru (WILD [192.168.1.24]) by exchange.universe.dart.spb with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2650.21)
	id XPK2PAVK; Tue, 19 Dec 2000 20:01:03 +0300
Content-Length: 1422
Message-ID: <XFMail.001219200110.diwil@dataart.com>
X-Mailer: XFMail 1.4.0 on FreeBSD
X-Priority: 3 (Normal)
Content-Type: text/plain; charset=KOI8-R
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
Date: Tue, 19 Dec 2000 20:01:10 +0300 (MSK)
Reply-To: diwil@dataart.com
Sender: diwil@runnet-gw.marketsite.ru
From: Dmitry Dicky <diwil@dataart.com>
To: freebsd-hackers@freebsd.org
Subject: recvfrom() and signals
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

Hello fellows,

I just faced with a problem of a strange (may be not documented)
recvfrom() behaviour.

The fragment of the code is:
...
        signal(SIGALRM, timeouttrap);
        alarm(10);
        i = recvfrom(sock, buf, len, 0, from, fromlen);
        printf("%d bytes received\n",i);
.... 
void timeouttrap(int sig)
{
        printf(">> %d", sig);
        return;
}

I use non blocking socket and it receives data with no problems.
When alarm occures, the signal delivered to the process and alarm handler
prints a signal number. As I understand after this recvfrom should
return -1 and errno should be set to EINTR.

BUt, upon signal delivery (actually any signal, CHLD for example)
recvfrom() still hangs the program execution and awaits data.

However, man pages say that recvfrom() will return -1 if the call has been
interrupted.

Is this a system bug or just my misunderstanding?

Thank you in advance,
Dmitry.

-- 
**********************************************************************
   ("`-''-/").___..--''"`-._     (\         Dimmy the Wild     UA1ACZ
    `6_ 6  )   `-.  (     ).`-.__.`)        DataArt Enterprises, Inc. 
    (_Y_.)'  ._   )  `._ `. ``-..-'         Serpukhovskaja street, 10
  _..`--'_..-_/  /--'_.' ,'                 Saint Petersburg,  Russia
 (il),-''  (li),'  ((!.-'                   +7 (812) 3261780, 5585314
**********************************************************************


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message