Re: Libraries using longjmp for error handling

From	Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups	comp.lang.c
Subject	Re: Libraries using longjmp for error handling
Date	2023-09-28 18:24 -0700
Organization	A noiseless patient Spider
Message-ID	<86y1gphiur.fsf@linuxsc.com> (permalink)
References	<65SQM.565977$9o89.411905@fx05.ams4> <wwvpm23d9fr.fsf@LkoBDZeT.terraraq.uk> <pan$6f4ce$6edf891e$2b5c40c1$f8f989c1@invalid.invalid> <AE3RM.402236$kCld.195109@fx08.ams4> <871qejf62x.fsf@bsb.me.uk>

Show all headers | View raw

Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

> Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> writes:
>
>> On 9/28/2023 6:52 AM, Blue-Maned_Hawk wrote:
>>
>>> Personally, i think that, at least for a library, an error
>>> should _only_ be communicated by return value.  If more complex
>>> information is required, then the return value can be made more
>>> complex.
>
> ...
>
>> Error handling in libraries is a thorny subject, and I could go
>> on a long rant on it.  The short summary is simply this:  error
>> handling is rife with incompetence, and incompetent designs.
>> Even in languages that ostensibly provide better mechanisms than
>> C, the details are usually poorly documented and under-specified
>> [1].
>
> If it's done well, the result is not even "error handling" -- it's
> just what the function returns.  For example, a lookup in a table
> of integers in Haskell returns a type that is, in effect "maybe an
> integer" The return will be either "Nothing" or something like
> "Just 42".

In languages that support it this approach is a good way to deal
with cases like this, I agree.  But to me it falls in a different
category than error handling.  An error condition is something
like an allocation (eg malloc()) failure, or a broken pipe.  Not
finding something in a table means whoever was responsible for
adding things to the table didn't add it - in other words it was
entirely a consequence of events that are under the program's
control.  The issue is how to deal with an unpredictable, and
usually very rare, event that is not something the program has
control over.  Typically these kinds of situations need a
different sort of mechanism than loading up the return value
of every function call.

Thread

Libraries using longjmp for error handling (was: Re: More on NNTP testing) Blue-Maned_Hawk <bluemanedhawk@invalid.invalid> - 2023-09-27 22:52 +0000
  Re: Libraries using longjmp for error handling (was: Re: More on NNTP testing) Johann 'Myrkraverk' Oskarsson <johann@myrkraverk.invalid> - 2023-09-28 08:19 +0800
    Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-28 02:18 +0100
      Re: Libraries using longjmp for error handling Blue-Maned_Hawk <bluemanedhawk@invalid.invalid> - 2023-09-28 22:30 +0000
        Re: Libraries using longjmp for error handling scott@slp53.sl.home (Scott Lurndal) - 2023-09-28 22:33 +0000
          Re: Libraries using longjmp for error handling Anton Shepelev <anton.txt@gmail.moc> - 2023-09-29 01:41 +0300
            Re: Libraries using longjmp for error handling scott@slp53.sl.home (Scott Lurndal) - 2023-09-28 23:45 +0000
          Re: Libraries using longjmp for error handling Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-28 17:35 -0700
            Re: Libraries using longjmp for error handling David Brown <david.brown@hesbynett.no> - 2023-09-29 16:49 +0200
      Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-28 18:24 -0700
        Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-29 03:19 +0100
          Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-29 07:46 -0700
            Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-29 21:02 +0100
              Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-29 21:56 -0700
                Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-10-01 00:06 +0100
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-30 20:35 -0700
                Re: Libraries using longjmp for error handling Anton Shepelev <anton.txt@gmail.moc> - 2023-10-01 14:44 +0300
                Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-10-01 15:45 +0100
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-10-01 09:28 -0700
                Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-10-01 20:49 +0100
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-10-02 02:31 -0700
                Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-10-02 23:55 +0100
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-10-03 05:01 -0700
            Re: Libraries using longjmp for error handling Anton Shepelev <anton.txt@gmail.moc> - 2023-09-29 23:58 +0300
              Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-10-01 02:52 -0700
                Re: Libraries using longjmp for error handling Anton Shepelev <anton.txt@gmail.moc> - 2023-10-01 14:33 +0300
  Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-28 01:48 +0100
  Re: Libraries using longjmp for error handling (was: Re: More on NNTP testing) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-28 05:11 +0000
    Re: Libraries using longjmp for error handling (was: Re: More on NNTP testing) Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-28 06:26 +0000
  Re: Libraries using longjmp for error handling (was: Re: More on NNTP testing) Anton Shepelev <anton.txt@gmail.moc> - 2023-09-28 16:02 +0300
    Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-28 14:44 +0100
      Re: Libraries using longjmp for error handling Anton Shepelev <anton.txt@gmail.moc> - 2023-09-28 18:31 +0300
        Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-28 16:43 +0000
          Re: Libraries using longjmp for error handling scott@slp53.sl.home (Scott Lurndal) - 2023-09-28 17:00 +0000
            Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-28 17:16 +0000
            Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-28 19:38 +0100
          Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-28 16:05 -0700
            Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-29 00:26 +0000
              Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-28 23:20 -0700
            Re: Libraries using longjmp for error handling Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-28 18:31 -0700
              Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-29 03:24 +0100
                Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-29 03:12 +0000
              Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-28 22:45 -0700
                Re: Libraries using longjmp for error handling Spiros Bousbouras <spibou@gmail.com> - 2023-09-29 12:02 +0000
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-29 08:10 -0700
                Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-29 17:03 +0100
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-29 10:15 -0700
                Re: Libraries using longjmp for error handling gazelle@shell.xmission.com (Kenny McCormack) - 2023-09-29 17:17 +0000
                Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-29 18:53 +0000
                Re: Libraries using longjmp for error handling Anton Shepelev <anton.txt@gmail.moc> - 2023-09-29 18:11 +0300
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-29 10:20 -0700
                Re: Libraries using longjmp for error handling Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2023-09-29 11:30 -0700
                Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-29 18:31 +0000
        Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-28 19:27 +0100
          Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-28 20:24 +0000
            Re: Libraries using longjmp for error handling Ben Bacarisse <ben.usenet@bsb.me.uk> - 2023-09-28 22:23 +0100
              Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-28 15:43 -0700
              Re: Libraries using longjmp for error handling Kaz Kylheku <864-117-4973@kylheku.com> - 2023-09-28 23:11 +0000
                Re: Libraries using longjmp for error handling Anton Shepelev <anton.txt@gmail.moc> - 2023-09-29 17:23 +0300
                Re: Libraries using longjmp for error handling Tim Rentsch <tr.17687@z991.linuxsc.com> - 2023-09-29 08:19 -0700
        Re: Libraries using longjmp for error handling David Brown <david.brown@hesbynett.no> - 2023-09-28 21:57 +0200
  Re: Libraries using longjmp for error handling Richard Kettlewell <invalid@invalid.invalid> - 2023-09-30 09:37 +0100

csiph-web