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

From "Alf P. Steinbach" <alf.p.steinbach@gmail.com>
Newsgroups comp.lang.c++
Subject Re: recovering from std::bad_alloc in std::string reserve
Date 2021-05-26 18:33 +0200
Organization A noiseless patient Spider
Message-ID <s8lt9d$tf0$1@dont-email.me> (permalink)
References <s8hkt2$liv$1@dont-email.me>

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On 2021-05-25 03:46, Lynn McGuire wrote:
> I am getting std::bad_alloc from the following code when I try to 
> reserve a std::string of size 937,180,144:
> 
> std::string filename = getFormsMainOwner () -> getOutputFileName ();
> FILE * pOutputFile = nullptr;
> errno_t err = fopen_s_UTF8 ( & pOutputFile, filename.c_str (), "rt");
> if (err == 0)
> {
>      std::string outputFileBuffer;
>          //  need to preallocate the space in case the output file is a 
> gigabyte or more, PMR 6408
>      fseek (pOutputFile, 0, SEEK_END);
>      size_t outputFileLength = ftell (pOutputFile) + 42;  // give it 
> some slop
>      fseek (pOutputFile, 0, SEEK_SET);
>      outputFileBuffer.reserve (outputFileLength);

[snip]

In the above code `ftell` will fail in Windows if the file is 2GB or 
more, because in Windows, even in 64-bit Windows, the `ftell` return 
type `long` is just 32 bits.

However, the C++ level iostreams can report the file size correctly:


----------------------------------------------------------------------------
#include <stdio.h>      // fopen, fseek, ftell, fclose
#include <stdlib.h>     // EXIT_...

#include <iostream>
#include <fstream>
#include <stdexcept>        // runtime_error
using namespace std;

auto hopefully( const bool e ) -> bool { return e; }
auto fail( const char* s ) -> bool { throw runtime_error( s ); }

struct Is_zero {};
auto operator>>( int x, Is_zero ) -> bool { return x == 0; }

const auto& filename = "large_file";

void c_level_check()
{
     struct C_file
     {
         FILE* handle;
         ~C_file() { if( handle != 0 ) { fclose( handle ); } }
     };

     auto const f = C_file{ fopen( ::filename, "rb" ) };
     hopefully( !!f.handle )
         or fail( "fopen failed" );
     fseek( f.handle, 0, SEEK_END )
         >> Is_zero()
         or fail( "fseek failed, probably rather biggus filus" );
     const long pos = ftell( f.handle );
     hopefully( pos >= 0 )
         or fail( "ftell failed" );
     cout << "`ftell` says the file is " << pos << " byte(s)." << endl;
}

void cpp_level_check()
{
     auto f = ifstream( ::filename, ios::in | ios::binary );
     f.seekg( 0, ios::end );
     const ifstream::pos_type pos = f.tellg();
     hopefully( pos != -1 )
         or fail( "ifstream::tellg failed" );
     cout << "`ifstream::tellg` says the file is " << pos << " bytes." 
<< endl;
}

void cpp_main()
{
     try {
         c_level_check();
     } catch( const exception& x ) {
         cerr << "!" << x.what() << endl;
         cpp_level_check();
     }
}

auto main() -> int
{
     try {
         cpp_main();
         return EXIT_SUCCESS;
     } catch( const exception& x ) {
         cerr << "!" << x.what() << endl;
     }
     return EXIT_FAILURE;
}
-------------------------------------------------------------------------------

When I tested this with `large_file` as a copy of the roughly 4GB 
"Bad.Boys.for.Life.2020.1080p.WEB-DL.DD5.1.H264-FGT.mkv", I got


[c:\root\dev\explore\filesize]
 > b
!ftell failed
`ifstream::tellg` says the file is 4542682554 bytes.


- Alf

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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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