Re: [PATCH] scanf.3: Do not mention the ERANGE error

Alejandro Colomar
2022-12-09T18:59:34Z

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Hi Ian,

On 12/8/22 13:34, Ian Abbott wrote:
> The `scanf()` function does not intentionally set `errno` to `ERANGE`.
> That is just a side effect of the code that it uses to perform
> conversions. It also does not work as reliably as indicated in the
> 'man' page when the target integer type is narrower than `long`.
> Typically (at least in glibc) for target integer types narrower than
> `long`, the number has to exceed the range of `long` (for signed
> conversions) or `unsigned long` (for unsigned conversions) for `errno`
> to be set to `ERANGE`.
>
> Documenting `ERANGE` in the ERRORS section kind of implies that
> `scanf()` should return `EOF` when an integer overflow is encountered,
> which it doesn't (and doing so would violate the C standard).
>
> Just remove any mention of the `ERANGE` error to avoid confusion.
>
> Fixes: 646af540e467 ("Add an ERRORS section documenting at least some of the errors that may occur for scanf().")
> Cc: Michael Kerrisk <mtk.manpages@gmail.com>
> Signed-off-by: Ian Abbott <abbotti@mev.co.uk>

I see. How about saying something like "it may also fail for any of any errors
that functions used to perform the conversions may fail"?

Cheers,

Alex

> ---
> man3/scanf.3 | 7 -------
> 1 file changed, 7 deletions(-)
>
> diff --git a/man3/scanf.3 b/man3/scanf.3
> index ba470a5c1..c5ff59f45 100644
> --- a/man3/scanf.3
> +++ b/man3/scanf.3
> @@ -576,10 +576,6 @@ is NULL.
> .TP
> .B ENOMEM
> Out of memory.
> -.TP
> -.B ERANGE
> -The result of an integer conversion would exceed the size
> -that can be stored in the corresponding integer type.
> .SH ATTRIBUTES
> For an explanation of the terms used in this section, see
> .BR attributes (7).
> @@ -609,9 +605,6 @@ The functions
> and
> .BR sscanf ()
> conform to C89 and C99 and POSIX.1-2001.
> -These standards do not specify the
> -.B ERANGE
> -error.
> .PP
> The
> .B q

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

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