Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.c > #382076

Re: Is C ready to become a safer language?

From Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups comp.lang.c
Subject Re: Is C ready to become a safer language?
Date 2024-02-07 20:59 -0800
Organization None to speak of
Message-ID <87jznfh7p6.fsf@nosuchdomain.example.com> (permalink)
References <uq1jnk$1qebo$2@dont-email.me>

Show all headers | View raw


Thiago Adams <thiago.adams@gmail.com> writes:
> Let's say C compilers can detect all sorts of bugs at compile time.
>
> How would C compilers report that? As an error or a warning?
>
> Let's use this sample:
>
> int main() {
>     int a = 1;
>     a = a / 0;
> }
>
> GCC says:
>
> warning: division by zero is undefined [-Wdivision-by-zero]
>     5 |  a = a / 0;
>       |        ^ ~
>
> In case GCC or any other compiler reports this as an error, then C
> programmers would likely complain. Am I right?

Someone will always complain, but a conforming compiler can report this
as a fatal error.

Division by zero has undefine behavior.  Under the standard's definition
of undefined behavior, it says:

    NOTE

    Possible undefined behavior ranges from ignoring the situation
    completely with unpredictable results, to behaving during
    translation or program execution in a documented manner
    characteristic of the environment (with or without the issuance
    of a diagnostic message), to terminating a translation or
    execution (with the issuance of a diagnostic message).

Though it's not quite that simple.  Rejecting the program if the
compiler can't prove that the division will be executed would IMHO
be non-conforming.  Code that's never executed has no behavior, so it
doesn't have undefined behavior.

But of course any compiler can reject anything it likes in
non-conforming mode.  See for example "gcc -Werror".

But even ignoring that, a culture of paying very close attention to
non-fatal warnings could go a long way towards making C safer (assuming
compilers are clever enough to issue good warnings).

[...]

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for Medtronic
void Void(void) { Void(); } /* The recursive call of the void */

Back to comp.lang.c | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 01:01 -0300
  Re: Is C ready to become a safer language? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-02-08 04:40 +0000
    Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-08 05:00 +0000
    Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 09:20 -0300
      Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-08 17:02 +0000
        Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 14:17 -0300
          Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 14:19 -0300
          Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 09:57 -0800
      Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 09:45 -0800
        Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 14:56 -0300
  Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-08 04:58 +0000
    Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-07 21:33 -0800
  Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-07 20:59 -0800
    Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-08 09:17 +0100
      Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 09:48 -0300
        Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-08 14:42 +0000
        Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-08 16:25 +0100
          Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 13:15 -0300
            Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-08 21:42 +0100
      Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 08:04 -0800
        Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-08 16:14 +0000
          Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-08 08:32 -0800
          Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 08:19 +0100
            Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 07:46 +0000
              Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 09:33 +0100
                Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 10:03 +0000
                Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 11:17 +0100
                Re: Is C ready to become a safer language? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-09 10:24 +0000
                Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 11:24 +0000
                Re: Is C ready to become a safer language? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-09 13:28 +0000
                Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 14:04 +0000
                Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 15:03 +0100
                ustent on that. Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-09 16:01 +0000
                Re: ustent on that. David Brown <david.brown@hesbynett.no> - 2024-02-09 18:00 +0100
                Re: ustent on that. Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-10 01:20 +0000
                Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-09 12:45 +0000
                Re: Is C ready to become a safer language? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2024-02-09 13:01 +0000
                Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 15:08 +0100
              Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-09 08:48 -0800
        Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 08:14 +0100
          Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-09 08:28 -0800
            Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-09 20:15 +0100
    Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 02:28 -0800
      Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 16:15 -0800
        Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 23:22 -0800
          Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-11 00:12 -0800
            Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-11 23:48 -0800
              Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-18 15:28 -0800
                Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-23 10:35 -0700
  Re: Is C ready to become a safer language? Richard Kettlewell <invalid@invalid.invalid> - 2024-02-08 15:37 +0000
    Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-08 13:25 -0300
  Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-08 16:30 +0000
    Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-09 17:59 -0800
      Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-10 20:22 +0000
        Re: Is C ready to become a safer language? Richard Harnden <richard.nospam@gmail.invalid> - 2024-02-10 21:30 +0000
        Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-10 21:49 +0000
          Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-10 20:44 -0300
            Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 13:06 +0100
              Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-11 15:43 -0300
                Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-11 13:33 -0800
                Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-12 11:32 +0100
          Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 00:02 +0000
            Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 17:39 -0800
            Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-11 02:46 +0000
              Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 12:24 +0000
                Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 15:06 +0100
                Re: Is C ready to become a safer language? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-02-11 18:32 +0000
            Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 13:15 +0100
        Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 16:31 -0800
          Re: Is C ready to become a safer language? Thiago Adams <thiago.adams@gmail.com> - 2024-02-11 15:57 -0300
            Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-11 13:47 -0800
        Re: Is C ready to become a safer language? vallor <vallor@cultnix.org> - 2024-02-11 00:40 +0000
          Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 01:06 +0000
          Re: Is C ready to become a safer language? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-02-10 17:51 -0800
            Re: Is C ready to become a safer language? David Brown <david.brown@hesbynett.no> - 2024-02-11 13:27 +0100
          Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 19:54 -0800
            Re: Is C ready to become a safer language? vallor <vallor@cultnix.org> - 2024-02-13 06:22 +0000
          Re: Is C ready to become a safer language? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-02-11 11:01 +0000
            Re: Is C ready to become a safer language? Richard Harnden <richard.nospam@gmail.invalid> - 2024-02-11 11:31 +0000
              Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 12:38 +0000
                Re: Is C ready to become a safer language? Richard Harnden <richard.nospam@gmail.invalid> - 2024-02-11 13:23 +0000
                Re: Is C ready to become a safer language? bart <bc@freeuk.com> - 2024-02-11 14:17 +0000
        Re: Is C ready to become a safer language? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-02-10 22:21 -0800

csiph-web