Re: realloc() - frequency, conditions, or experiences about relocation?

From	Ben Bacarisse <ben@bsb.me.uk>
Newsgroups	comp.lang.c, sci.stat.math
Subject	Re: realloc() - frequency, conditions, or experiences about relocation?
Followup-To	comp.lang.c
Date	2024-06-19 22:24 +0100
Organization	A noiseless patient Spider
Message-ID	<87o77wsk18.fsf@bsb.me.uk> (permalink)
References	(5 earlier) <20240617180249.96dfaafa89392827aa162434@g{oogle}mail.com> <v4tuvf$1qto5$1@dont-email.me> <v4u7dm$1t2pu$1@dont-email.me> <875xu5t066.fsf@bsb.me.uk> <v4v58t$230rh$1@dont-email.me>

Cross-posted to 2 groups.

Followups directed to: comp.lang.c

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David Brown <david.brown@hesbynett.no> writes:

> On 19/06/2024 17:36, Ben Bacarisse wrote:
>> Growing the buffer exponentially is simple and effective.
>
> Yes, that's the general way to handle buffers when you don't know what size
> they should be.
>
> A better solutions for this sort of program is usually, as you say, asking
> the OS for the file size (there is no standard library function for getting
> the file size, but it's not hard to do for any realistic target OS).  And
> then for big files, prefer mmap to reading the file into a buffer.
>
> It's only really for unsized "files" such as piped input that you have no
> way of getting the size, and then exponential growth is the way to go.
> Personally, I'd start with a big size (perhaps 10 MB) that is bigger than
> you are likely to need in practice, but small enough that it is negligible
> on even vaguely modern computers. Then the realloc code is unlikely to be
> used (but it can still be there for completeness).

There are other uses that have nothing to do with files.  I have a small
dynamic array library (just a couple of function) that I use for all
sorts of things.  I can read a file or parse tokens or input a line just
by adding characters.  Because of its rather general use, I don't start
with a large buffer (though the initial size can be set).

-- 
Ben.

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realloc() - frequency, conditions, or experiences about relocation? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-06-17 08:08 +0200
  Re: realloc() - frequency, conditions, or experiences about relocation? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-16 23:34 -0700
  Re: realloc() - frequency, conditions, or experiences about relocation? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-17 10:18 +0100
    Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-17 10:31 +0100
      Re: realloc() - frequency, conditions, or experiences about relocation? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-17 10:55 +0100
        Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-17 13:45 +0100
          Re: realloc() - frequency, conditions, or experiences about relocation? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-17 15:33 +0100
            Re: realloc() - frequency, conditions, or experiences about relocation? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2024-06-17 18:10 +0300
              Re: realloc() - frequency, conditions, or experiences about relocation? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-18 00:09 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-18 11:19 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-18 11:46 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-29 00:14 +0000
                Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-07-02 10:18 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? Ben Bacarisse <ben@bsb.me.uk> - 2024-07-02 16:39 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-07-03 23:48 +0000
                Re: realloc() - frequency, conditions, or experiences about relocation? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-24 09:32 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? David Brown <david.brown@hesbynett.no> - 2024-06-24 19:19 +0200
                Indefinite pronouns [was:Re: realloc() - frequency, conditions, or experiences about relocation?] Anton Shepelev <anton.txt@gmail.moc> - 2024-06-20 02:51 +0300
                Re: Indefinite pronouns vallor <vallor@cultnix.org> - 2024-06-20 00:34 +0000
                Re: Indefinite pronouns David Brown <david.brown@hesbynett.no> - 2024-06-21 12:59 +0200
                Re: Indefinite pronouns Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-21 10:31 -0700
                Re: Indefinite pronouns [was:Re: realloc() - frequency, conditions, or experiences about relocation?] gazelle@shell.xmission.com (Kenny McCormack) - 2024-06-20 12:10 +0000
                Re: Indefinite pronouns [was: Re: <something technical>] Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-06-20 15:04 +0200
                Re: Indefinite pronouns [was:Re: realloc() - frequency, conditions, or experiences about relocation?] Cri-Cri <cri@cri.cri.invalid> - 2024-06-21 00:55 +0000
                Re: Indefinite pronouns [was:Re: realloc() - frequency, conditions, or experiences about relocation?] Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-20 23:23 -0700
            Re: realloc() - frequency, conditions, or experiences about relocation? Richard Harnden <richard.nospam@gmail.invalid> - 2024-06-17 16:15 +0100
              Re: realloc() - frequency, conditions, or experiences about relocation? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-17 13:05 -0700
            Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-17 16:36 +0100
          Re: realloc() - frequency, conditions, or experiences about relocation? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2024-06-17 18:02 +0300
            Re: realloc() - frequency, conditions, or experiences about relocation? "David Jones" <dajhawk18xx@@nowhere.com> - 2024-06-18 17:59 +0000
            Re: realloc() - frequency, conditions, or experiences about relocation? davidd02@tpg.com.au (David Duffy) - 2024-06-19 06:48 +0000
              Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-19 10:12 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-19 16:36 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? David Brown <david.brown@hesbynett.no> - 2024-06-19 19:41 +0200
                Re: realloc() - frequency, conditions, or experiences about relocation? Ben Bacarisse <ben@bsb.me.uk> - 2024-06-19 22:24 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? David Brown <david.brown@hesbynett.no> - 2024-06-20 13:22 +0200
                Re: realloc() - frequency, conditions, or experiences about relocation? Anton Shepelev <anton.txt@gmail.moc> - 2024-06-20 01:53 +0300
              Re: realloc() - frequency, conditions, or experiences about relocation? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2024-06-19 15:20 +0300
            Re: realloc() - frequency, conditions, or experiences about relocation? Rich Ulrich <rich.ulrich@comcast.net> - 2024-07-02 00:51 -0400
              Re: realloc() - frequency, conditions, or experiences about relocation? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-07-01 22:10 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? Rich Ulrich <rich.ulrich@comcast.net> - 2024-07-02 11:45 -0400
              Re: realloc() - frequency, conditions, or experiences about relocation? Paul <nospam@needed.invalid> - 2024-07-02 03:02 -0400
                Re: realloc() - frequency, conditions, or experiences about relocation? Rich Ulrich <rich.ulrich@comcast.net> - 2024-07-02 11:52 -0400
                Re: realloc() - frequency, conditions, or experiences about relocation? Rich Ulrich <rich.ulrich@comcast.net> - 2024-07-02 11:58 -0400
                Re: realloc() - frequency, conditions, or experiences about relocation? Paul <nospam@needed.invalid> - 2024-07-02 15:09 -0400
                Re: realloc() - frequency, conditions, or experiences about relocation? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-02 16:54 -0400
                Re: realloc() - frequency, conditions, or experiences about relocation? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-07-02 16:58 -0400
          Re: realloc() - frequency, conditions, or experiences about relocation? scott@slp53.sl.home (Scott Lurndal) - 2024-06-17 16:58 +0000
            Re: realloc() - frequency, conditions, or experiences about relocation? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-17 13:12 -0700
          Re: realloc() - frequency, conditions, or experiences about relocation? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-17 16:39 -0700
            Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-18 06:12 +0100
            Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-18 09:56 +0200
      Re: realloc() - frequency, conditions, or experiences about relocation? David Brown <david.brown@hesbynett.no> - 2024-06-17 20:11 +0200
  Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-17 11:22 +0200
    Re: realloc() - frequency, conditions, or experiences about relocation? Vir Campestris <vir.campestris@invalid.invalid> - 2024-06-20 21:08 +0100
      Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-21 21:12 +0200
        Re: realloc() - frequency, conditions, or experiences about relocation? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-24 08:40 +0000
          Re: realloc() - frequency, conditions, or experiences about relocation? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-24 02:55 -0700
            Re: realloc() - frequency, conditions, or experiences about relocation? David Brown <david.brown@hesbynett.no> - 2024-06-24 13:40 +0200
              Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-24 18:50 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? scott@slp53.sl.home (Scott Lurndal) - 2024-06-24 18:20 +0000
                Re: realloc() - frequency, conditions, or experiences about relocation? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-24 14:28 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-06-25 00:22 +0100
                Re: realloc() - frequency, conditions, or experiences about relocation? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-24 18:31 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-25 07:06 +0000
                Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-25 10:38 +0200
                Re: realloc() - frequency, conditions, or experiences about relocation? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-26 00:51 +0000
              Re: realloc() - frequency, conditions, or experiences about relocation? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-24 12:33 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-24 21:48 +0200
              Re: realloc() - frequency, conditions, or experiences about relocation? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-24 22:59 +0000
            Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-24 16:19 +0200
            Re: realloc() - frequency, conditions, or experiences about relocation? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-25 07:02 +0000
              Re: realloc() - frequency, conditions, or experiences about relocation? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-25 03:05 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? Richard Damon <richard@damon-family.org> - 2024-06-25 07:21 -0400
                Re: realloc() - frequency, conditions, or experiences about relocation? Phil Carmody <pc+usenet@asdf.org> - 2024-06-28 11:01 +0300
                Re: realloc() - frequency, conditions, or experiences about relocation? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-28 04:04 -0700
                Re: realloc() - frequency, conditions, or experiences about relocation? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-06-28 06:37 -0400
                Re: realloc() - frequency, conditions, or experiences about relocation? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-28 04:05 -0700
              Re: realloc() - frequency, conditions, or experiences about relocation? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-06-28 06:36 -0400
          Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-24 16:16 +0200
            Down the hall, past the water cooler, third door on the left... (Was: realloc() - frequency, conditions, or experiences about) relocation? gazelle@shell.xmission.com (Kenny McCormack) - 2024-06-24 15:44 +0000
              Re: Down the hall, past the water cooler, third door on the left... (Was: realloc() - frequency, conditions, or experiences about) relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-24 20:16 +0200
  Re: realloc() - frequency, conditions, or experiences about relocation? David Brown <david.brown@hesbynett.no> - 2024-06-17 14:15 +0200
    Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-17 14:18 +0200
  Re: realloc() - frequency, conditions, or experiences about relocation? Janis Papanagnou <janis_papanagnou+ng@hotmail.com> - 2024-06-17 15:21 +0200
  Re: realloc() - frequency, conditions, or experiences about relocation? scott@slp53.sl.home (Scott Lurndal) - 2024-06-17 16:50 +0000
    Re: realloc() - frequency, conditions, or experiences about relocation? Michael S <already5chosen@yahoo.com> - 2024-06-17 20:20 +0300
      Re: realloc() - frequency, conditions, or experiences about relocation? scott@slp53.sl.home (Scott Lurndal) - 2024-06-17 19:02 +0000
  Re: realloc() - frequency, conditions, or experiences about relocation? Rosario19 <Ros@invalid.invalid> - 2024-06-18 11:50 +0200
  Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-25 10:48 +0200
    Re: realloc() - frequency, conditions, or experiences about relocation? Vir Campestris <vir.campestris@invalid.invalid> - 2024-06-25 11:55 +0100
      Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-25 13:28 +0200
        Re: realloc() - frequency, conditions, or experiences about relocation? Vir Campestris <vir.campestris@invalid.invalid> - 2024-06-26 12:15 +0100
          Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-26 15:01 +0200
    Re: realloc() - frequency, conditions, or experiences about relocation? DFS <nospam@dfs.com> - 2024-06-25 09:56 -0400
      Re: realloc() - frequency, conditions, or experiences about relocation? Bonita Montero <Bonita.Montero@gmail.com> - 2024-06-25 16:16 +0200

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