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Re: Trying to figure out how to dynamically re-allocate strings while concatenating

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Am 05.08.2012 02:00, schrieb Keith Thompson:
> That is, of course, very good advice.
> 
> On the other hand, whether it matters depends on what you intend to do
> once you've detected an allocation failure.
> 
>     char *buf = malloc(100);
>     if (buf == NULL) {
>         /* malloc failed */
>     }
> 
>     char *temp = realloc(buf, 200);
>     if (temp == NULL) {
>         /* realloc failed */
>     }
> 
> So how can you recover from a failure to allocate memory?  You could
> just try again, but it will probably just fail again.  You could fall
> back to a less memory-intensive, but perhaps slower, algorithm, but
> I don't think I've ever seen code in the real world that does that.
> 
> A very common response to a memory allocation failure is to
> terminate the program, ideally after doing some cleanup (such as
> saving temporary files, restoring the display to a sane state,
> printing and/or logging an error message, etc.)  But if the
> program is about to terminate anyway, then losing the pointer to
> your original buffer isn't going to make much difference, and you
> probably might as well write:
> 
>     buf = malloc(buf, 200);
> 
> On the other other hand, cleaning up after yourself is a good habit, and
> it's possible that calling free(buf) will free up memory that's needed
> by your cleanup code.

Very well stated, this error checking for valid dynamic allocations is
often overestimated, treated almost religiously.

If you don't know how to recover from such a failure other than to
abort the program, there is really no point in it. (But implying also
that for specialized code where you know what to do, you should do
it.)

What these things often do on the other hand is code obfuscation. I
think in many cases having simple and readable code is much more
important.

Jens

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Trying to figure out how to dynamically re-allocate strings while concatenating Shriramana Sharma <jamadagni@gmail.com> - 2012-08-04 07:12 -0700
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating Xavier Roche <xroche@free.fr.NOSPAM.invalid> - 2012-08-04 16:17 +0200
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating Xavier Roche <xroche@free.fr.NOSPAM.invalid> - 2012-08-04 16:22 +0200
    Re: Trying to figure out how to dynamically re-allocate strings while concatenating Shriramana Sharma <jamadagni@gmail.com> - 2012-08-04 07:25 -0700
      Re: Trying to figure out how to dynamically re-allocate strings while concatenating Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-04 16:04 +0100
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating "Heinrich Wolf" <invalid@invalid.invalid> - 2012-08-04 16:29 +0200
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-08-04 10:52 -0400
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating pete <pfiland@mindspring.com> - 2012-08-04 12:27 -0400
    Re: Trying to figure out how to dynamically re-allocate strings while concatenating Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-08-04 13:56 -0400
      Re: Trying to figure out how to dynamically re-allocate strings while  concatenating pete <pfiland@mindspring.com> - 2012-08-04 17:12 -0400
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating pete <pfiland@mindspring.com> - 2012-08-04 12:42 -0400
    Re: Trying to figure out how to dynamically re-allocate strings while concatenating Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-08-04 14:00 -0400
    Re: Trying to figure out how to dynamically re-allocate strings while concatenating Keith Thompson <kst-u@mib.org> - 2012-08-04 17:00 -0700
      Re: Trying to figure out how to dynamically re-allocate strings while concatenating pete <pfiland@mindspring.com> - 2012-08-04 20:48 -0400
      Re: Trying to figure out how to dynamically re-allocate strings while concatenating Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-05 09:22 +0200
        Re: Trying to figure out how to dynamically re-allocate strings while concatenating Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-05 12:49 +0100
          Re: Trying to figure out how to dynamically re-allocate strings while concatenating Jens Gustedt <jens.gustedt@loria.fr> - 2012-08-05 17:12 +0200
          Re: Trying to figure out how to dynamically re-allocate strings while concatenating Keith Thompson <kst-u@mib.org> - 2012-08-05 13:17 -0700
            Re: Trying to figure out how to dynamically re-allocate strings while concatenating Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-05 22:53 +0100
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating Shriramana Sharma <jamadagni@gmail.com> - 2012-08-04 19:20 -0700
  Re: C Vs Asm i use for cat function "io_x" <a@b.c.invalid> - 2012-08-05 08:15 +0200
    Re: C Vs Asm i use for cat function "BartC" <bc@freeuk.com> - 2012-08-05 10:22 +0100
      Re: C Vs Asm i use for cat function "Heinrich Wolf" <invalid@invalid.invalid> - 2012-08-05 17:00 +0200
        Re: C Vs Asm i use for cat function Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-08-05 16:20 +0100
      Re: C Vs Asm i use for cat function "io_x" <a@b.c.invalid> - 2012-08-05 19:51 +0200
        Re: C Vs Asm i use for cat function "BartC" <bc@freeuk.com> - 2012-08-05 21:04 +0100
  Re: Trying to figure out how to dynamically re-allocate strings while concatenating Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-08-10 10:45 +0300

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