Re: [PATCH] ioctl_ns.2, stat.2: drop unneeded uintmax_t casts.

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

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Hi Jakub!

On 8/30/22 21:58, Jakub Wilk wrote:
> major() and minor() return unsigned int,
> so the typecasts to uintmax_t are not needed.

I don't remember all of the details.  I remember having discussed 
exactly this, but can't find it in the archives.

FreeBSD returns signed int <https://www.freebsd.org/cgi/man.cgi?major>. 
Linux returns unsigned int.  So the type that can hold values in both 
types would be intmax_t.

I guess I used uintmax_t because of the %x conversion specifier, which 
requires an unsigned number, and so the only issue will be that the 
number will be very high if the original value was negative.

Admittedly, if you pass an int to %x, it's going to work in the same way 
as uintmax_t is working right now.

It's not clear if that's Undefined Behavior 
<https://stackoverflow.com/q/4664100/6872717>, but it's certainly going 
to work, so I'll apply your patch.

Thanks,

Alex

> 
> Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
> ---
>   man2/ioctl_ns.2 | 12 ++++++------
>   man2/stat.2     |  6 +++---
>   2 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/man2/ioctl_ns.2 b/man2/ioctl_ns.2
> index 95b39ccac..02c1dab11 100644
> --- a/man2/ioctl_ns.2
> +++ b/man2/ioctl_ns.2
> @@ -293,9 +293,9 @@ main(int argc, char *argv[])
>               exit(EXIT_FAILURE);
>           }
>           printf("Device/Inode of owning user namespace is: "
> -               "[%jx,%jx] / %ju\en",
> -               (uintmax_t) major(sb.st_dev),
> -               (uintmax_t) minor(sb.st_dev),
> +               "[%x,%x] / %ju\en",
> +               major(sb.st_dev),
> +               minor(sb.st_dev),
>                  (uintmax_t) sb.st_ino);
>   
>           close(userns_fd);
> @@ -323,9 +323,9 @@ main(int argc, char *argv[])
>               perror("fstat\-parentns");
>               exit(EXIT_FAILURE);
>           }
> -        printf("Device/Inode of parent namespace is: [%jx,%jx] / %ju\en",
> -               (uintmax_t) major(sb.st_dev),
> -               (uintmax_t) minor(sb.st_dev),
> +        printf("Device/Inode of parent namespace is: [%x,%x] / %ju\en",
> +               major(sb.st_dev),
> +               minor(sb.st_dev),
>                  (uintmax_t) sb.st_ino);
>   
>           close(parent_fd);
> diff --git a/man2/stat.2 b/man2/stat.2
> index 585a20484..bdd6d15e3 100644
> --- a/man2/stat.2
> +++ b/man2/stat.2
> @@ -481,9 +481,9 @@ main(int argc, char *argv[])
>           exit(EXIT_FAILURE);
>       }
>   
> -    printf("ID of containing device:  [%jx,%jx]\en",
> -           (uintmax_t) major(sb.st_dev),
> -           (uintmax_t) minor(sb.st_dev));
> +    printf("ID of containing device:  [%x,%x]\en",
> +           major(sb.st_dev),
> +           minor(sb.st_dev));
>   
>       printf("File type:                ");
>   

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

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