Hi Walter,
On 23 November 2017 at 10:23, walter harms <wharms@xxxxxx> wrote:
>
>
> 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.
Indeed. So, I changed the text to:
The error numbers that correspond to each symbolic name vary
across UNIX systems, and even across different architectures on
Linux. Therefore, numeric values are not included in the list of
error names below. Portable applications should use the symbolic
error names (rather than explicit error numbers). The perror(3)
and strerror(3) functions can be used to convert these names to
corresponding textual error messages.
> 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".
I'm not sure what you are referring to with the preceding line.
Thanks for the input, Walter.
Cheers,
Michael
> 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
>>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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