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

From	David Brown <david.brown@hesbynett.no>
Newsgroups	comp.lang.c
Subject	Re: realloc() - frequency, conditions, or experiences about relocation?
Date	2024-06-24 13:40 +0200
Organization	A noiseless patient Spider
Message-ID	<v5bluo$thpd$1@dont-email.me> (permalink)
References	(1 earlier) <v4ov8h$j2q2$1@raubtier-asyl.eternal-september.org> <v52270$2nli8$1@dont-email.me> <v54jac$3a4p2$1@raubtier-asyl.eternal-september.org> <v5bbd3$rhao$2@dont-email.me> <875xtyu0kk.fsf@nosuchdomain.example.com>

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On 24/06/2024 11:55, Keith Thompson wrote:

> Something else that occurs to me: If a shrinking realloc() never fails
> in practice, then any code you write to handle a failure won't be
> tested.
> 

That is always a problem with allocation functions.  Have you ever known 
a non-pathological malloc() to fail?

I think, in fact, there's a good argument for ignoring the possibility 
of malloc (and calloc and realloc) failures for most PC code.  There is 
virtually no chance of failure in reality, and if you get one, there is 
almost never a sensible way to deal with it - you just kick the can down 
the road by having functions return NULL until something gives up and 
stops the program with an error message.  You might as well just let the 
OS kill the program when you try to access memory at address 0.

I've seen more than enough error handling code that has never been 
tested in practice - including error handling code with bugs that lead 
to far worse problems than just killing the program.

Of course such treatment is not appropriate for all allocations (or 
other functions that could fail).  But often I think it is better to 
write clearer and fully testable (and tested!) code which ignores 
hypothetical errors, rather than some of the untestable and untested 
jumbles that are sometimes seen in an attempt to "handle" allocation 
failures.

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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> - 2024-07-08 19:34 +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? Anton Shepelev <anton.txt@g{oogle}mail.com> - 2024-07-08 20:01 +0300
              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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