Re: [PATCH] register_printf_speficier.3, register_printf_modifier.3, register_printf_type.3: Add new manual page and links

[Alex Colomar <alx.manpages@gmail.com>]

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On 9/19/22 00:36, Alex Colomar wrote:
> On 9/19/22 00:16, Alex Colomar wrote:
>> And it seems I also need some help with my own example, since I
>> discovered there's some sort of undefined behavior in it (just run
>> it several times and see; some work, but some do show weird stuff
>> for the cases where with modifiers that make the number wider than
>> unsigned int).  If you find the undefined behavior, please show
>> me.  I'll continue debugging, anyway.
>>
> 
> 
> This is the UB I'm experiencing:
> 
> alx@dell7760:~/tmp$ ./a.out | head
> ....----....----....----....----
> 0000000000000000000000000000000000000000000000011111111111110100000000000000000000000001011110;
> 0000000000000000000000000000000000000000000000011111111111110100000000000000000000000001011110;
> 00000001011110;
> 00000001011110;
> 00000001011110;
> 0000000000000000000000000000000000000000000000011111111111110100000000000000000000000001011110;
> 0000000000000000000000000000000000000000000000011111111111110100000000000000000000000001011110;
> ....----....----....----....----
> 0b00000001011110;
> alx@dell7760:~/tmp$ ./a.out | head
> ....----....----....----....----
> 00000001011110;
> 00000001011110;
> 00000001011110;
> 00000001011110;
> 00000001011110;
> 00000001011110;
> 00000001011110;
> ....----....----....----....----
> 0b00000001011110;
> 

Oh, and I have extra zeros, but that's a bug I introduced today.  Before 
that, the other one is still there. :/

> 
> The first run is wrong, and the second one is correct.  The relevant 
> printf(3) lines are:
> 
> 
>             printf("....----....----....----....----\n");
>             printf("%llb;\n", 0x5Ellu);
>             printf("%lB;\n", 0x5Elu);
>             printf("%b;\n", 0x5Eu);
>             printf("%hB;\n", 0x5Eu);
>             printf("%hhb;\n", 0x5Eu);
>             printf("%jb;\n", (uintmax_t)0x5E);
>             printf("%zb;\n", (size_t)0x5E);
>             printf("....----....----....----....----\n");
>             printf("%#b;\n", 0x5Eu);
> 
> 
> Cheers,
> 
> Alex
> 
> 

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


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