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From: "marc.glisse at normalesup dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/46906] istreambuf_iterator is late? Date: Mon, 05 Sep 2011 12:39:00 -0000 [thread overview] Message-ID: <bug-46906-4-Fd3Ox48xcr@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-46906-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46906 --- Comment #7 from Marc Glisse <marc.glisse at normalesup dot org> 2011-09-05 12:38:13 UTC --- (In reply to comment #6) > 1) The fact that repeated calls of operator* without intervening operator++ > calls produce the same result for a given iterator object is required by > expression *a: > > "The expression (void)*a, *a is equivalent to *a." There are operations between the 2 calls to operator*. > This explains the repeated values '1' and '1' from it1 and '2' and '2' from > it2. Oh, are you saying that this rule has priority over the one that says that operator* just forwards to sgetc? That would actually require istreambuf_iterator to keep the last value in cache the way libstdc++ does. If that's the case, I believe it would be worth mentioning in the standard (it's not just me, when I filed the bug report I had found at least one implementation that did not cache, Roguewave (haven't checked more recent Apache versions)). For a vector, touching the vector between 2 dereferencing of the same iterator invalidates the iterator. Here, my guess was that it didn't invalidate the iterator and we should blindly call sgetc. But your explanation makes sense.
next prev parent reply other threads:[~2011-09-05 12:39 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2010-12-12 15:26 [Bug libstdc++/46906] New: " marc.glisse at normalesup dot org 2010-12-12 17:38 ` [Bug libstdc++/46906] " paolo.carlini at oracle dot com 2010-12-12 18:01 ` marc.glisse at normalesup dot org 2010-12-12 18:28 ` paolo.carlini at oracle dot com 2011-09-05 9:49 ` daniel.kruegler at googlemail dot com 2011-09-05 10:00 ` marc.glisse at normalesup dot org 2011-09-05 11:11 ` daniel.kruegler at googlemail dot com 2011-09-05 12:39 ` marc.glisse at normalesup dot org [this message] 2011-09-05 12:57 ` daniel.kruegler at googlemail dot com 2011-09-05 14:02 ` marc.glisse at normalesup dot org 2011-09-05 14:17 ` daniel.kruegler at googlemail dot com 2011-09-05 15:06 ` marc.glisse at normalesup dot org 2012-08-22 20:00 ` glisse at gcc dot gnu.org 2023-05-17 14:46 ` redi at gcc dot gnu.org
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