From: Ian Lance Taylor <iant@google.com>
To: Tom Browder <tom.browder@gmail.com>
Cc: GCC-help <gcc-help@gcc.gnu.org>
Subject: Re: Core dump constructing a C++ string with NULL
Date: Thu, 13 Jan 2011 20:59:00 -0000 [thread overview]
Message-ID: <mcrbp3ko6zr.fsf@google.com> (raw)
In-Reply-To: <AANLkTin_hTLeBJQfTAyS_-hX4Bq4FoghFNX9tAtBpraK@mail.gmail.com> (Tom Browder's message of "Thu, 13 Jan 2011 13:56:26 -0600")
Tom Browder <tom.browder@gmail.com> writes:
> It would be nice if this would construct an empty string:
>
> #include <string>
> std::string s(0);
>
> At the moment that gives a core dump.
>
> Is that defined behavior according to the standard? If not, what
> about a g++ enhancement?
The standard says that you may only pass a valid pointer to the
std::string constructor. You are passing an invalid pointer, so your
code is undefined.
As to whether libstdc++ should check for NULL, that is a perennial
question: should we slow down the library a tiny bit for everybody in
order to do better handling of an undefined case for those who find it
more convenient? There is no clearly correct answer.
Ian
next prev parent reply other threads:[~2011-01-13 20:59 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-13 19:56 Tom Browder
2011-01-13 20:04 ` Brian Budge
2011-01-13 20:50 ` Jonathan Wakely
2011-01-13 20:59 ` Ian Lance Taylor [this message]
2011-01-14 16:20 ` Tom Browder
2011-01-14 16:47 ` Jonathan Wakely
2011-01-14 17:00 ` Tom Browder
2011-01-14 17:05 ` Jonathan Wakely
2011-01-14 17:17 ` Jonathan Wakely
2011-01-14 17:39 ` Tom Browder
2011-01-14 17:38 ` Ian Lance Taylor
2011-01-14 17:44 ` Tom Browder
2011-01-14 17:48 ` Brian Budge
2011-01-15 12:33 ` Tom Browder
2011-01-15 13:52 ` Jonathan Wakely
2011-01-15 14:06 ` Tom Browder
2011-01-15 14:12 ` Jonathan Wakely
2011-01-15 14:15 ` Jonathan Wakely
2011-01-15 15:06 ` Tom Browder
2011-01-14 18:04 ` Jonathan Wakely
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