Re: [PATCH] errno.3: Add values for all errors

[walter harms <wharms-fPG8STNUNVg@public.gmane.org>]

Am 23.11.2017 10:07, schrieb Michael Kerrisk (man-pages):
> On 11/23/2017 09:31 AM, Christoph Hellwig wrote:
>> On Wed, Nov 22, 2017 at 07:15:45PM -0500, Wesley Aptekar-Cassels wrote:
>>> This patch documents the values of error numbers on linux. This is
>>> something that is in the OpenBSD errno man page, which I find quite
>>> useful.
>>
>> Error numbers are different for different architectures.
> 
> I was just about to say the same.
> 
> Someone else recently proposed the same change, and I should have
> thought then to add the text that I have added just now to errno(3).
> Hopefully this goes someway to addressing your requirements, Wesley.
> 
> New text:
> 
>        On  Linux, the error numbers that correspond to each symbolic name
>        vary somewhat across architectures.  Therefore, numeric values are
>        not  included in the list of error names below.  On any particular
>        system, one can obtain a list of all symbolic error names and  the
>        corresponding error numbers using the errno(1) command:
> 
If i read this that would mean the values differ between the linux architectures only.
I do not ting that was intended. What about that:


Portability:
 Programmers should use always the symbolic names as that the value of errno may vary
 across different systems. Always use strerror (3) (or compareable) to translate
 the errno code into a human readable string.

note: errno (1) is a nice programm and it could be mentioned but a propper programm
      simply should not say things like "Error: 13".

re,
 wh


>            $ errno -l
>            EPERM 1 Operation not permitted
>            ENOENT 2 No such file or directory
>            ESRCH 3 No such process
>            EINTR 4 Interrupted system call
>            EIO 5 Input/output error
>            ...
> 
>        The  errno(1) command can also be used to look up individual error
>        numbers and names as in the following examples:
> 
>            $ errno 2
>            ENOENT 2 No such file or directory
>            $ errno ESRCH
>            ESRCH 3 No such process
> 
> Cheers,
> 
> Michael
> 
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