Date: Mon, 1 Jun 1998 18:30:15 +0200 (MET DST) From: Joerg Schilling <schilling@fokus.gmd.de> To: mike@smith.net.au, schilling@fokus.gmd.de Cc: freebsd-current@FreeBSD.ORG Subject: Re: cdrecord trouble on currnet Message-ID: <199806011630.SAA17075@sherwood.gmd.de>
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>From mike@antipodes.cdrom.com Mon Jun 1 18:17:40 1998
>> You cannot deal with this problem:
>> =
>> Systems that define _SC_PAGESIZE or _SC_PAGE_SIZE (HP-UX)
>> don't support getpagesize() so there is no way to fix this
>> in runtime except if you introduce an additional =
>> =
>> HAVE_GETPAGESIZE
>> =
>> in the autoconfiguration.
>> =
>> But even then the code would be badly readable. =
>This is a problem with the design of cdrecord, insofar as it's fairly
Sorry, this is a problem for evryone who wants to write portable code.
But FreeBSD seems to ignore this issue.
You may have a functional sysconf(_SC_PAGESIZE) _and_ getpagesize() if you
like to be able to run portable applications but you cannot have a non
functional sysconf(_SC_PAGESIZE).
This looks to me like Microsofts tried to create a Posix environment that
is Posix compliant on the paper but would prevent you from running real world
Posix applications on it.
>clear it wasn't designed for portability. Probably the most expedient
>move would be not to pretend that cdrecord is compliant with the default
>POSIX API on FreeBSD for now, and wind back the presented API to one
>that it is. That's what _POSIX_VERSION is all about.
Right, when I started to write cdrecord, I thought that it would only run
on SunOS 4.x and SunOS 5.x but now it is one of the most portable application
that I made.
>Thanks for the HP-UX pointer; I'll take note that _SC_PAGESIZE is =
>implicitly assumed to mean DONT_HAVE_GETPAGESIZE.
>> I would prefer if the sysconf code would call getpagesize() in userland=
>=2E
>This would defeat the entire purpose of sysconf(), which is to pass =
>opaque constants to the kernel. I don't see any merit in hacking a =
You should read the Posix standard:
The POSIX standard does not describe the behaviour of a kernel
interface but the interface of callbable functions in the c-library.
>perfectly compliant interface to deal with (pardon my saying it) buggy =
>applications.
I would call a sysconf implementation that is not functional for sysconf(_SC_PAGESIZE)
although getpagesize() exists buggy.
Jörg
EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
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