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From: Jakub Jelinek <jakub@redhat.com>
To: "Richard B. Johnson" <linux-os@analogic.com>
Cc: Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: System call v.s. errno
Date: Wed, 4 May 2005 09:42:24 -0400	[thread overview]
Message-ID: <20050504134224.GE17420@devserv.devel.redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.61.0505040849150.8743@chaos.analogic.com>

On Wed, May 04, 2005 at 09:22:09AM -0400, Richard B. Johnson wrote:
> Does anybody know for sure if global 'errno' is supposed to
> be altered after a successful system call? I'm trying to
> track down a problem where system calls return with EINTR
> even though all signal handlers are set with SA_RESTART in
> the flags. It appears as though there may be a race somewhere
> because if I directly set errno to 0x1234, within a few
> hundred system calls, it gets set to EINTR even though all
> system calls seemed to return 'good'. This makes it
> hard to trace down the real problem.

http://www.opengroup.org/onlinepubs/009695399/functions/errno.html
is very clear on this.  Unless indicated that errno is valid after a call
(for many syscalls it is valid when the syscall returns -1), errno has
unspecified value.

	Jakub

  parent reply	other threads:[~2005-05-04 13:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-05-04 13:22 System call v.s. errno Richard B. Johnson
2005-05-04 13:30 ` Måns Rullgård
2005-05-04 13:41 ` Wichert Akkerman
2005-05-04 13:42 ` Jakub Jelinek [this message]
2005-05-04 13:49   ` Richard B. Johnson
2005-05-04 16:03     ` Stephen Hemminger
2005-05-04 13:55 ` Martin Waitz
2005-05-04 14:22 ` Arjan van de Ven

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