Subject: Re: [PATCH] Restartable poll(2)
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Naoaki Maeda <maeda.naoaki@jp.fujitsu.com>
Cc: akpm@osdl.org, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
In-Reply-To: <20050117.113142.41643336.maeda.naoaki@jp.fujitsu.com>
References: <20050114.205214.74752151.maeda.naoaki@jp.fujitsu.com>
	 <20050117.113142.41643336.maeda.naoaki@jp.fujitsu.com>
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Date: Mon, 17 Jan 2005 12:23:39 +0000
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On Llu, 2005-01-17 at 02:31, Naoaki Maeda wrote:
> Hi,
> 
> Does nobody think a system call is interrupted by SIGSTOP is
> strange behaviour?

Not really

> According to the man page, both of poll(2) and select(2) can be
> interrupted by signals, but select(2) interrupted by SIGSTOP is
> automatically restarted, and poll(2) isn't. 

Correct - select and poll come from different worlds with different
viewpoints on signal behaviour.

> If it is a specification of Linux, using job control or ptrace()
> isn't safe because it changes the behaviour of target programs.

Programs must always deal with system call -EINTR responses
appropriately.

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