Re: recovering from std::bad_alloc in std::string reserve

Path	csiph.com!eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
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	Sun, 06 Jun 2021 16:33:04 -0700
Organization	None to speak of
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David Brown <david.brown@hesbynett.no> writes:
> On 06/06/2021 07:02, Keith Thompson wrote:
>> David Brown <david.brown@hesbynett.no> writes:
>>> On 04/06/2021 02:36, Scott Lurndal wrote:
>> [...]
>>>> Perhaps, but gcc generally documents all the functions that will
>>>> be inlined in their texinfo documentation, and div is not included
>>>> in the list of math functions that automatically get  builtin status
>>>> at least in GCC 4.8.   Since they're up to GCC11 now, they may have
>>>> added it to the list.
>>>
>>> It has not (because of the weakly specified "div_t" struct that is
>>> determined by the library implementation and not the standards or the
>>> compiler).
>>>
>>> <https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html>
>> 
>> This could be done if a future C standard specified the representation
>> of type div_t (as it does for complex types).
>
> One of the suggested ways for handling this situation for gcc is, in
> fact, to use a complex type as a container for the div_t results.  It
> would use the gcc extension of complex integer types (Gaussian integers,
> I suppose), precisely because it is a suitable pair of numbers whose
> structure is known to the compiler.  This is just one of these odd
> things in compilers that seems simple from the outside, but has subtle
> complications in practice.

Sure, but the type div_t is still defined in the <stdlib.h> or <cstdlib>
header, and gcc has to work with arbitrary library implementations.

The C standard's requirements for the representation of complex types:

    Each complex type has the same representation and alignment
    requirements as an array type containing exactly two elements of the
    corresponding real type; the first element is equal to the real
    part, and the second element to the imaginary part, of the complex
    number.

could easily be reworked to specify the representation of div_t
(and ldiv_t, and lldvi_t, and intmaxdiv_t).  I strongly suspect
that all existing implementations already define the *div_t types
consistently, with quot at offset 0 and rem following it.  If the
layout were specified, gcc could optimize calls to the *div()
functions (assuming it knows that the library that will be used
is conforming).

[...]

-- 
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 */

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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