From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <bonzini@gnu.org>
Subject: Re: poll() emulation in git
Date: Wed, 05 Sep 2012 17:25:49 +0200
Message-ID: <50476EFD.2000500@gnu.org>
References: <00c001cd8b59$028e41c0$07aac540$@schmitz-digital.de> <50474001.5030407@gnu.org> <00d801cd8b6b$844bbcd0$8ce33670$@schmitz-digital.de>
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Cc: 'Junio C Hamano' <gitster@pobox.com>, git@vger.kernel.org,
	'Erik Faye-Lund' <kusmabite@gmail.com>, bug-gnulib@gnu.org
To: Joachim Schmitz <jojo@schmitz-digital.de>
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Il 05/09/2012 15:36, Joachim Schmitz ha scritto:
>>> > > Does your system have a working FIONREAD ioctl for pipes?
>> > 
>> > It does have FIONREAD ioctl. Whether it works properly is to be determined...
>> > I'll test if you could show me how?
> Oh, now I see what you aimed at, but no, that Mac OS X method doesn't work for me, I tried (at least I think I did).
> 
> And <sys/ioctl.h> has
> /*
>  * Normal IOCTL's supported by the socket interface
>  */
> #define FIONREAD        _IOR(0, 8, _ioctl_int)       /* Num of bytes to read */
> #define FIONBIO         _IOW(0, 9, _ioctl_int)       /* Non-blocking I/O     */
> 
> So these seem to be supported on sockets only, I guess.
> And indeed the man pages for ioctl confirms:
> 
>           Valid values for the request parameter for AF_INET or
>           AF_INET6 sockets are:
> 
> 
>           FIONREAD  Gets the number of bytes available for reading and
>                     stores it at the int pointed at by arg.
> 
> 
> So not even AF_UNIX sockets, not to mention pipes...

So there's no way you can support POLLHUP.  Your system is quite
crippled. :(

Paolo