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Groups > comp.lang.c > #18157

Re: Mechanism to generate annotated "error codes"

From Don Y <this@isnotme.com>
Newsgroups comp.lang.c
Subject Re: Mechanism to generate annotated "error codes"
Date 2012-03-03 13:03 -0700
Organization Aioe.org NNTP Server
Message-ID <jittf4$bf7$1@speranza.aioe.org> (permalink)
References <jiojq3$3cm$1@speranza.aioe.org> <ea871b51-f766-4da3-ab1a-169434004f0d@p7g2000yqk.googlegroups.com> <jisie1$1qf$1@speranza.aioe.org> <71e9ea6e-f120-48e3-b139-ac68447963db@f2g2000yqh.googlegroups.com> <44sjhp8pp3.fsf@lowell-desk.lan>

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Hi Lowell,

On 3/3/2012 12:11 PM, Lowell Gilbert wrote:
> Malcolm McLean<malcolm.mclean5@btinternet.com>  writes:
>
>> On Mar 3, 7:49 am, Don Y<t...@isnotme.com>  wrote:
>>>
>>>> Centralised error systems mean that code will break if you try to move
>>>> it to a different project.
>>>
>>> And, when our images are merged, we magically end up with the
>>> union of error messages and "codes" that we have individually
>>> used.
>>>
>> You've described the problem.
>>
>> Fred scatters his code with
>>
>> log_error(ERR_TOOMANYFILESOPEN);
>>
>> Bert does the same with
>>
>> fprintf_error(EC_FILECOUNTEXCEEDED, "Too many files open (%d)\n",
>> Nfiles);
>>
>> Now when we merge Fred's code with Bert's, what's going to happen?
>
> That's the wrong question, because the answer necessarily depends on the
> relationship between Fred and Bert. If they are independent third-party
> library developers, you're not likely to get them to use *your* error-

If they are truly independent (i.e., you are purchasing a COTS library),
then you *wrap* their library functions to map their error_t's to *your*
error scheme.

E.g.,

void *
MyMalloc(
   size_t size,
   error_t *error
) {
   void *ptr;

   if (size > MAX_ALLOCATION) {
MakeErrorCode(Err_TooBig,
               "Allocation too large.",
               "The requested piece of memory was larger than the
                  maximum supported for the process."
               )
      *error = Err_TooBig;
      return NULL;
   }

   ptr = malloc(size);
   if (ptr == NULL) {
MakeErrorCode(Err_NoMemory,
               "Out of memory"
               "The free memory pool has been exhausted."
               )

      *error = Err_NoMemory;
      return NULL;
   }

   return ptr;
}

[Note that I am not trying to be "friendly" with my error messages
in this example.  Also, the semantics for this example try to
resemble the semantics expected of traditional malloc.  I would,
instead, return a "Result_t"]

> reporting system now. If they both work for you, then you can require
> them to use any system you want, and any sane system should work
> (although simpler systems may be more effort to scale up).
>
> In practice, the former case usually means that each set of third-party
> code has its own type for errors, and the functions you call them from
> will report errors upwards according to their own convention that need
> have nothing to do with the third-party code. But you're limited to the
> information that their API already provide.

Of course!  Just as if you want to change the syntax of "decimal
strings" to prohibit leading (or TRAILING!) zeroes yet *mandate*
at least one character on each *side* of the decimal point, you
can't use strtod(3).  Or, if you want to conditionally be able to
limit the range of values that can be represented by such
strings, etc.

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Thread

Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 12:48 -0700
  Re: Mechanism to generate annotated "error codes" Willem <willem@toad.stack.nl> - 2012-03-01 21:29 +0000
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 16:53 -0700
  Re: Mechanism to generate annotated "error codes" William Ahern <william@wilbur.25thandClement.com> - 2012-03-01 14:13 -0800
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 22:07 -0700
  Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-01 17:53 -0500
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-01 23:05 -0700
      Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-02 01:50 -0500
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 00:43 -0700
          Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-03 17:58 -0500
            Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-04 03:16 -0500
              Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 13:47 -0700
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 13:45 -0700
              Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-04 18:37 -0500
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 22:12 -0700
                Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-08 01:41 -0500
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-09 14:34 -0700
  Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 00:30 -0700
    Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-02 02:05 -0800
      Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-02 10:47 +0000
      Re: Mechanism to generate annotated "error codes" gazelle@shell.xmission.com (Kenny McCormack) - 2012-03-02 14:18 +0000
      Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 10:46 -0700
        Re: Mechanism to generate annotated "error codes" James Kuyper <jameskuyper@verizon.net> - 2012-03-02 14:08 -0500
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 12:38 -0700
        Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-02 22:57 +0000
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 17:14 -0700
            Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-03 02:25 +0000
            Re: Mechanism to generate annotated "error codes" James Kuyper <jameskuyper@verizon.net> - 2012-03-03 06:10 -0500
              Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-03 16:12 -0500
        Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-03 04:04 -0800
          Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-03 15:05 +0000
            Re: Mechanism to generate annotated "error codes" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-03-03 16:25 +0000
          Re: Mechanism to generate annotated "error codes" Shao Miller <sha0.miller@gmail.com> - 2012-03-03 16:26 -0500
            Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-03 13:40 -0800
      Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-03 12:03 +1300
        Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-02 15:45 -0800
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-02 17:18 -0700
      Re: Mechanism to generate annotated "error codes" blp@cs.stanford.edu (Ben Pfaff) - 2012-03-02 15:08 -0800
      Re: Mechanism to generate annotated "error codes" "BartC" <bc@freeuk.com> - 2012-03-03 10:30 +0000
        Re: Mechanism to generate annotated "error codes" James Kuyper <jameskuyper@verizon.net> - 2012-03-03 06:19 -0500
        Re: Mechanism to generate annotated "error codes" Phil Carmody <thefatphil_demunged@yahoo.co.uk> - 2012-03-03 15:15 +0200
        Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-03 14:52 +0000
          Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 07:39 -0800
            Re: Mechanism to generate annotated "error codes" Jonathan Leffler <jleffler@earthlink.net> - 2012-03-03 23:56 -0800
              Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 09:20 +1300
                Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-04 13:28 -0800
                Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 10:56 +1300
          Re: Mechanism to generate annotated "error codes" "BartC" <bc@freeuk.com> - 2012-03-03 17:02 +0000
        Re: Mechanism to generate annotated "error codes" Keith Thompson <kst-u@mib.org> - 2012-03-03 12:30 -0800
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 19:15 -0700
      Re: Mechanism to generate annotated "error codes" Kaz Kylheku <kaz@kylheku.com> - 2012-03-04 03:20 +0000
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 11:03 -0700
      Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 16:31 -0700
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 23:04 -0700
  Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-02 22:13 -0800
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 00:49 -0700
      Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 03:32 -0800
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 12:04 -0700
          Re: Mechanism to generate annotated "error codes" Lowell Gilbert <lgusenet@be-well.ilk.org> - 2012-03-03 15:06 -0500
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 14:38 -0700
          Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 12:15 -0800
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 16:51 -0700
              Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-04 14:08 -0800
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 15:56 -0700
      Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 03:45 -0800
        Re: Mechanism to generate annotated "error codes" Lowell Gilbert <lgusenet@be-well.ilk.org> - 2012-03-03 14:11 -0500
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 13:03 -0700
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 12:32 -0700
      Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 15:04 -0700
        Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-04 11:09 +1300
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 16:55 -0700
            Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-04 13:04 +1300
              Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 18:24 -0700
        Re: Mechanism to generate annotated "error codes" Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-03-03 14:30 -0800
          Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-03 17:06 -0700
  Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 10:09 +1300
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 16:03 -0700
      Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 13:26 +1300
        Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-04 22:21 -0700
          Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-05 20:46 +1300
            Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-05 10:54 -0700
              Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-06 10:02 +1300
                Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-05 16:09 -0700
            Re: Mechanism to generate annotated "error codes" "BartC" <bc@freeuk.com> - 2012-03-06 10:54 +0000
              Re: Mechanism to generate annotated "error codes" Ian Collins <ian-news@hotmail.com> - 2012-03-07 07:22 +1300
  Re: Mechanism to generate annotated "error codes" gordonb.8sa24@burditt.org (Gordon Burditt) - 2012-03-06 08:51 -0600
    Re: Mechanism to generate annotated "error codes" Don Y <this@isnotme.com> - 2012-03-06 11:21 -0700

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