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From: "mimomorin at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/109891] Null pointer special handling in ostream's
 operator << for C-strings
Date: Thu, 18 May 2023 15:08:14 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109891

--- Comment #6 from Michel Morin <mimomorin at gmail dot com> ---
True. Detectable is not correct =E2=80=94 that's "maybe-detectable" at most=
, and the
bug is not silent. In a code that I checked, the buggy code (`std::cout <<
NullCharPtr;`) is the last printing call to std::cout, so I failed to see t=
he
side-effect.

The patchlet using `_GLIBCXX_DEBUG_PEDASSERT` works fine. Actually I would =
like
`_GLIBCXX_DEBUG_ASSERT` (because I've been using `_GLIBCXX_DEBUG` but never
`_GLIBCXX_DEBUG_PEDANTIC`), but I guess using `_GLIBCXX_DEBUG_PEDASSERT` ra=
ther
than `_GLIBCXX_DEBUG_ASSERT` in this case is a delibarate choice.=