Re: C Strings and String Literals. (Was: Pascal rides again)

[Alejandro Colomar]

Hi Larry!

On 11/13/22 21:45, Larry McVoy wrote:
> None of this surprises me but it reminds me of how I described C to
> my older son who is learning computer science.
>
> C is sort of like driving a sports car on a narrow mountain road with
> no guard rails.  If you like to text while you drive, C is not for you.
> If you can't keep your eyes on the road, C is not for you.  If you are
> a bad driver (programmer, duh), C is not for you.  But if you are an
> expert driver, like to go fast, pay attention, C is just fine, great
> in fact.
>
> Source: been a C programmer for more than 40 years, have written
> commercially used products over and over again in C.  I love C, I get
> that it is not for everyone but it is an excellent language in the hands
> of expert programmers.
Hi Larry!

I missed your reply; would have CCd you too (but you probably will get it from 
the list anyway).  I agree most of the time, but there are still rough corners 
that need to be polished.  See below.


On 11/13/22 22:20, Alejandro Colomar wrote:
> See for example some (part of a) change that I did for optimizing some code, 
> where I transformed pointers to char to char arrays (following Ulrich Drepper's 
> article about libraries).  The global change using arrays instead of pointers 
> reduced the code size in a couple of KiB, IIRC, which for cache misses might be 
> an important thing.
>
>
> -static const char *log_levels[] = {
> +static const char  log_levels[][8] = {
>       "alert",
>       "error",
>       "warn",
>       "notice",
>       "info",
>       "debug",
>   };
>
>
> As a note, I used 8 for better alignment, but 7 would have been fine.  Now, 
> let's imagine that I append the following element to the array: "messages"? 
> Values of beta will give rise to dom!
>
>
> Do I really need to load a gun and point it to my feet just to get that 
> performance?  Wouldn't it be nice to use -Wunterminated-strings and let the 
> compiler yell at me if I write a string literal with 8 letters?  I mean, it 
> should be simple for a compiler to implement that, and I would be sooo much 
> happier!

This is not at all like driving a fast car and being an excellent driver.  This 
is like driving a fast car in that narrow mountain, and knowing that closing 
your eyes will make you even faster.  Will you close them?  :)

Did nobody in the last 40 years, or more, realize how ****ing unsafe that 
construct is?  Is the compiler warning so hard to implement?  Or maybe it exists 
but is not on by default and I never heard of it...

Cheers,

Alex

--
<http://www.alejandro-colomar.es/>

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