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

Groups > comp.lang.c > #385485

Re: C23 thoughts and opinions

Show key headers only | View raw

Lew Pitcher <lew.pitcher@digitalfreehold.ca> writes:

> On Sun, 02 Jun 2024 13:24:23 +0000, Kenny McCormack wrote:
>
>> In article <v3gou9$36n61$3@dont-email.me>,
>> Lawrence D'Oliveiro  <ldo@nz.invalid> wrote:
>>
>>> On Fri, 31 May 2024 17:55:13 -0500, Lynn McGuire wrote:
>>>
>>>>     while (1)
>>>
>>> Why not
>>>
>>>    while (true)
>>>
>>> or even
>>>
>>>    for (;;)
>>>
>>> ?
>
> I've always considered
>   for (;;)
> preferable over
>   while (1)
> as the for (;;) expression does not require the compiler to expand
> and evaluate a condition expression.
>
> For the for (;;), the compiler sees the token stream <LPAREN>
> <SEMICOLON> <SEMICOLON> <RPAREN>, and emits a closed loop, but
> with while (1), the compiler sees <LPAREN> <CONSTANT> <RPAREN>,

But the 'for (;;)' tokens need to be matched to a much more
complicated syntax, with three optional expression (one of
which might be a declaration) before assigning semantics.
There is actually a lot more to do when 'for (;;)' is used.

> and has to evaluate (either at compile time or at execution
> time) the value of the <CONSTANT> to determine whether or or
> not to emit the closed loop logic.

Both gcc and clang turn 'while (1)' into simple loops even
under -O0.  So it can't be that hard.

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

Thread

Re: C23 thoughts and opinions Lynn McGuire <lynnmcguire5@gmail.com> - 2024-05-31 17:55 -0500
  Re: C23 thoughts and opinions David Brown <david.brown@hesbynett.no> - 2024-06-01 15:30 +0200
  Re: C23 thoughts and opinions Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-02 03:29 +0000
    Re: C23 thoughts and opinions Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-01 23:31 -0700
    Re: C23 thoughts and opinions gazelle@shell.xmission.com (Kenny McCormack) - 2024-06-02 13:24 +0000
      Re: C23 thoughts and opinions Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2024-06-02 16:51 +0000
        Re: C23 thoughts and opinions Kaz Kylheku <643-408-1753@kylheku.com> - 2024-06-02 19:52 +0000
          Re: C23 thoughts and opinions Michael S <already5chosen@yahoo.com> - 2024-06-03 12:01 +0300
          Re: C23 thoughts and opinions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-03 13:31 -0700
            Re: C23 thoughts and opinions "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-03 14:02 -0700
              Re: C23 thoughts and opinions gazelle@shell.xmission.com (Kenny McCormack) - 2024-06-03 21:48 +0000
                Re: C23 thoughts and opinions David Brown <david.brown@hesbynett.no> - 2024-06-04 10:36 +0200
                Re: C23 thoughts and opinions "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-06-04 14:47 -0700
          Re: C23 thoughts and opinions bart <bc@freeuk.com> - 2024-06-03 23:43 +0100
            Re: C23 thoughts and opinions Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-06-03 16:23 -0700
              Re: C23 thoughts and opinions David Brown <david.brown@hesbynett.no> - 2024-06-04 10:47 +0200
            Re: C23 thoughts and opinions Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-06-04 02:20 +0000
              Re: C23 thoughts and opinions David Brown <david.brown@hesbynett.no> - 2024-06-04 10:47 +0200
            Re: C23 thoughts and opinions Kaz Kylheku <643-408-1753@kylheku.com> - 2024-06-04 05:25 +0000
        Re: C23 thoughts and opinions Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-06-03 13:29 -0700

csiph-web