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Groups > comp.lang.c++ > #79810
| From | Keith Thompson <Keith.S.Thompson+u@gmail.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: recovering from std::bad_alloc in std::string reserve |
| Date | 2021-05-27 15:58 -0700 |
| Organization | None to speak of |
| Message-ID | <87o8cvzsux.fsf@nosuchdomain.example.com> (permalink) |
| References | (2 earlier) <s8m48i$g6f$3@dont-email.me> <s8nbvd$5ah$1@dont-email.me> <s8oqn6$fbj$1@dont-email.me> <_CUrI.452334$ST2.205157@fx47.iad> <87sg27zu0i.fsf@nosuchdomain.example.com> |
Keith Thompson <Keith.S.Thompson+u@gmail.com> writes:
> scott@slp53.sl.home (Scott Lurndal) writes:
>> Lynn McGuire <lynnmcguire5@gmail.com> writes:
>>>On 5/27/2021 12:50 AM, Christian Gollwitzer wrote:
>>>> Am 26.05.21 um 20:32 schrieb Lynn McGuire: - Alf
>>>>>
>>>>> I have already replaced the fell code with _ftelli64.
>>>>>
>>>>> //Â get the size of the output file
>>>>> fseek (pOutputFile, 0, SEEK_END);
>>>>> __int64 outputFileLength = _ftelli64 (pOutputFile) + 42;Â // give it
>>>>> some slop
>>>>> int outputFileLengthInt = (int) outputFileLength;
>>>>
>>>> ...and here you restrict it to 2GB again, or worse, retrieve a negative
>>>> file size for sizes between 2GB and 4GB.
>>>>
>>>>
>>>> To prepare for a 64bit move, you should replace all size variables with
>>>> size_t for unsigned or ptrdiff_t for signed. That will correspond to a
>>>> 32bit integer in 32 bit and a 64 bit integer in 64 bit.
>>>>
>>>> Â Â Â Â Christian
>>>
>>>Done. With checking against SIZE_MAX before casting the variable to size_t.
>>
>> Why? size_t is guaranteed to hold the size of any object, which implies that
>> it must be large enough to accomodate an object the size of the virtual address
>> space. Generally it's minimum size in bits is the same as long.
>
> That's likely to be true, but it's not absolutely guaranteed.
My apologies, I was wrong.
> size_t is intended to hold the size of any single object, but it may
> not be able to hold the sum of sizes of all objects or the size of
> the virtual address space. An implementation might restrict the
> size of any single object to something smaller than the size of
> the entire virtual address space. (Think segments.)
I believe this is still correct.
> Also, I haven't found anything in the standard that says you
> can't at least try to create an object bigger than SIZE_MAX bytes.
> calloc(SIZE_MAX, 2) attempts to allocate such an object, and I don't
> see a requirement that it must fail. If an implementation lets you
> define a named object bigger than SIZE_MAX bytes, then presumably
> applying sizeof to it would result in an overflow, and therefore
> undefined behavior.
>
> Any reasonable implementation will simply make size_t big enough
> to hold the size of any object it can create, but I don't see a
> requirement for it.
The above is correct in C, but not in C++, which makes an additional
guarantee that C doesn't. C++17 21.2.4 [support.types.layout] says:
The type size_t is an implementation-defined unsigned integer type
that is large enough to contain the size in bytes of any object
(8.3.3).
--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Philips Healthcare
void Void(void) { Void(); } /* The recursive call of the void */
Back to comp.lang.c++ | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-24 20:46 -0500
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-24 20:50 -0500
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-24 20:52 -0500
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-25 07:47 +0300
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-25 12:20 -0500
Re: recovering from std::bad_alloc in std::string reserve Christian Gollwitzer <auriocus@gmx.de> - 2021-05-26 08:36 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-26 13:28 -0500
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-25 12:56 +0200
Re: recovering from std::bad_alloc in std::string reserve scott@slp53.sl.home (Scott Lurndal) - 2021-05-25 14:55 +0000
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-25 18:42 +0300
Re: recovering from std::bad_alloc in std::string reserve MrSpook_Ann1u@d0v_5eh1bqgd.com - 2021-05-25 16:10 +0000
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-25 18:23 +0200
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-25 19:57 +0300
Re: recovering from std::bad_alloc in std::string reserve MrSpook_ddZgr4t4@okc9_pd48oig5.info - 2021-05-26 07:15 +0000
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-26 09:22 +0200
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-26 10:54 +0300
Re: recovering from std::bad_alloc in std::string reserve MrSpook_dw5lvA4g@kak0_42x.edu - 2021-05-26 08:29 +0000
Re: recovering from std::bad_alloc in std::string reserve Nikolaj Lazic <nlazicBEZ_OVOGA@mudrac.ffzg.hr> - 2021-05-25 16:21 +0000
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-25 20:04 +0300
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-25 12:46 -0500
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-25 20:58 +0300
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-25 13:48 -0500
Re: recovering from std::bad_alloc in std::string reserve Nikolaj Lazic <nlazicBEZ_OVOGA@mudrac.ffzg.hr> - 2021-05-25 18:23 +0000
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-25 13:49 -0500
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-26 21:07 -0500
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-25 18:23 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-24 22:33 -0500
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-24 22:35 -0500
Re: recovering from std::bad_alloc in std::string reserve Juha Nieminen <nospam@thanks.invalid> - 2021-05-25 05:16 +0000
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-25 13:00 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-25 12:49 -0500
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-27 14:08 -0500
Re: recovering from std::bad_alloc in std::string reserve scott@slp53.sl.home (Scott Lurndal) - 2021-05-27 21:59 +0000
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-05-27 15:33 -0700
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-05-27 15:58 -0700
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-27 18:17 -0500
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-05-27 16:58 -0700
Re: recovering from std::bad_alloc in std::string reserve Öö Tiib <ootiib@hot.ee> - 2021-05-27 18:36 -0700
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-27 21:38 -0500
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-28 08:53 +0300
Re: recovering from std::bad_alloc in std::string reserve Bo Persson <bo@bo-persson.se> - 2021-05-28 09:47 +0200
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-05-27 19:54 -0700
Re: recovering from std::bad_alloc in std::string reserve Öö Tiib <ootiib@hot.ee> - 2021-05-27 21:02 -0700
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-05-28 12:09 -0700
Re: recovering from std::bad_alloc in std::string reserve scott@slp53.sl.home (Scott Lurndal) - 2021-05-28 20:26 +0000
Re: recovering from std::bad_alloc in std::string reserve Öö Tiib <ootiib@hot.ee> - 2021-05-28 17:10 -0700
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-05-29 11:47 +0200
Re: recovering from std::bad_alloc in std::string reserve "daniel...@gmail.com" <danielaparker@gmail.com> - 2021-05-30 15:15 -0700
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-05-31 08:33 +0200
Re: recovering from std::bad_alloc in std::string reserve "daniel...@gmail.com" <danielaparker@gmail.com> - 2021-05-31 08:21 -0700
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-05-31 18:13 +0200
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-05-31 14:43 -0700
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-05-31 14:44 -0700
Re: recovering from std::bad_alloc in std::string reserve "daniel...@gmail.com" <danielaparker@gmail.com> - 2021-05-31 15:20 -0700
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-01 11:17 -0700
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-01 20:25 +0200
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-01 16:55 -0700
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-02 09:06 +0200
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-05 17:50 -0700
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-06 11:10 +0200
Re: recovering from std::bad_alloc in std::string reserve Öö Tiib <ootiib@hot.ee> - 2021-06-06 04:07 -0700
Re: recovering from std::bad_alloc in std::string reserve Richard Damon <Richard@Damon-Family.org> - 2021-06-06 07:49 -0400
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-01 20:21 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-02 09:29 +0200
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-02 18:43 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-02 23:32 +0200
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-03 00:49 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-03 09:08 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-03 10:53 +0200
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-03 16:20 +0200
Re: recovering from std::bad_alloc in std::string reserve James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-06-03 11:20 -0400
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-03 19:04 +0200
Re: recovering from std::bad_alloc in std::string reserve scott@slp53.sl.home (Scott Lurndal) - 2021-06-03 22:24 +0000
Re: recovering from std::bad_alloc in std::string reserve Öö Tiib <ootiib@hot.ee> - 2021-06-03 16:27 -0700
Re: recovering from std::bad_alloc in std::string reserve scott@slp53.sl.home (Scott Lurndal) - 2021-06-04 00:36 +0000
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-04 08:46 +0200
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-05 22:02 -0700
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-06 11:17 +0200
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-06 18:39 +0200
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-06 16:33 -0700
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-07 08:41 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-06 17:46 +0200
Re: recovering from std::bad_alloc in std::string reserve MrSpook_Qfmtjdmi@nc6.com - 2021-06-06 14:11 +0000
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-03 16:43 +0200
Re: recovering from std::bad_alloc in std::string reserve Manfred <noname@add.invalid> - 2021-06-01 18:00 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-01 19:15 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-01 15:55 +0200
Re: recovering from std::bad_alloc in std::string reserve Bo Persson <bo@bo-persson.se> - 2021-06-01 13:59 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-06-01 13:26 -0500
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-01 08:29 +0200
Re: recovering from std::bad_alloc in std::string reserve Bo Persson <bo@bo-persson.se> - 2021-06-01 14:05 +0200
Re: recovering from std::bad_alloc in std::string reserve David Brown <david.brown@hesbynett.no> - 2021-06-01 15:58 +0200
Re: recovering from std::bad_alloc in std::string reserve James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-06-01 11:33 -0400
Re: recovering from std::bad_alloc in std::string reserve Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-06-01 10:52 -0700
Re: recovering from std::bad_alloc in std::string reserve James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-05-27 23:16 -0400
Re: recovering from std::bad_alloc in std::string reserve scott@slp53.sl.home (Scott Lurndal) - 2021-05-28 14:34 +0000
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-27 18:19 -0500
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-28 03:47 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-27 17:45 -0500
Re: recovering from std::bad_alloc in std::string reserve scott@slp53.sl.home (Scott Lurndal) - 2021-05-28 14:38 +0000
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-28 16:44 +0200
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-28 16:42 +0200
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-28 18:22 +0300
Re: recovering from std::bad_alloc in std::string reserve Paavo Helde <myfirstname@osa.pri.ee> - 2021-05-28 08:47 +0300
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-26 06:16 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-26 13:30 -0500
Re: recovering from std::bad_alloc in std::string reserve Bonita Montero <Bonita.Montero@gmail.com> - 2021-05-26 20:37 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-26 14:09 -0500
Re: recovering from std::bad_alloc in std::string reserve "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-05-26 18:33 +0200
Re: recovering from std::bad_alloc in std::string reserve Lynn McGuire <lynnmcguire5@gmail.com> - 2021-05-26 13:32 -0500
Re: recovering from std::bad_alloc in std::string reserve Christian Gollwitzer <auriocus@gmx.de> - 2021-05-27 07:50 +0200
Re: recovering from std::bad_alloc in std::string reserve "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2021-06-01 17:35 -0700
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