Date: Mon, 3 Sep 2001 07:03:37 +0400 From: "Andrey A. Chernov" <ache@nagual.pp.ru> To: Alfred Perlstein <bright@mu.org> Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/lib/libc/stdio setvbuf.c Message-ID: <20010903070334.A97368@nagual.pp.ru> In-Reply-To: <20010902214528.J81307@elvis.mu.org> References: <200109030235.f832ZAg46853@freefall.freebsd.org> <20010902214528.J81307@elvis.mu.org>
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On Sun, Sep 02, 2001 at 21:45:28 -0500, Alfred Perlstein wrote: > * Andrey A. Chernov <ache@FreeBSD.org> [010902 21:35] wrote: > > ache 2001/09/02 19:35:10 PDT > > > > Modified files: > > lib/libc/stdio setvbuf.c > > Log: > > When __SOPT is cleared, clear __SOFF too. > > > > NOTE: original stdio bug. > > What are you validating these changes against? POSIX? Solaris? Linux? Stdio try to optimize seeks internally to keep file offset in memory without additional fp->_seek, commonly lseek call (and use __SOFF for it). It can be done correctly only for regular files and when fp->_seek not changed to non-standard function. Character devices (f.e. normal stdio) often move pointer by themselfs, so keeping offset in memory for them leads to incorrect offset. Stdio try to detect regular files with fp->seek set to standard __seek and set __SOPT flag for them. It means that file can be optimized. __SOFF is one sort of optimizations, it means we have valid file offset in memory. When setvbuf.c clears __SOPT, no optimizations allowed including __SOFF, so __SOFF must be removed too. -- Andrey A. Chernov http://ache.pp.ru/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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