strcpy compared to POSIX strcpy

strcpy compared to POSIX strcpy

[Jonny Grant]

Hi Michael,

Returning to an old topic, noticed strcpy man page is different from the POSIX spec with regards to "terminating NUL character" or "null-terminated" shouldn't man pages should follow POSIX style writing "NUL"?

https://man7.org/linux/man-pages/man3/strcpy.3.html

https://man7.org/linux/man-pages/man3/strcpy.3p.html

https://pubs.opengroup.org/onlinepubs/9699919799/functions/strcpy.html

Another function even has nul in the name
https://man7.org/linux/man-pages/man3/strchrnul.3.html


Regards, Jonny

Re: strcpy compared to POSIX strcpy

[Michael Kerrisk (man-pages)]

Hi Jonny

On Mon, 29 Jun 2020 at 15:41, Jonny Grant <jg@jguk.org> wrote:
>
> Hi Michael,
>
> Returning to an old topic, noticed strcpy man page is different from the POSIX spec with regards to "terminating NUL character" or "null-terminated" shouldn't man pages should follow POSIX style writing "NUL"?
>
> https://man7.org/linux/man-pages/man3/strcpy.3.html
>
> https://man7.org/linux/man-pages/man3/strcpy.3p.html
>
> https://pubs.opengroup.org/onlinepubs/9699919799/functions/strcpy.html
>
> Another function even has nul in the name
> https://man7.org/linux/man-pages/man3/strchrnul.3.html

It's not so simple. In POSIX/SUS, you will find variously:

terminating NUL character
terminating NUL
terminating null character
terminating null byte

There's even one instance of "terminating NULL character" (in
<net/if.h>; I estimate it's a bug).

In the C standard (C11), "terminating null character" seems to be used
exclusively, but as I understand the C standard [char == byte] by
definition.

I've tried to consistently use "terminating null byte" across all
pages in man-pages. See also the discussion in man-pages(7).

Cheers,

Michael






-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/

Re: strcpy compared to POSIX strcpy

[Jonny Grant]

On 29/06/2020 21:30, Michael Kerrisk (man-pages) wrote:
> Hi Jonny
> 
> On Mon, 29 Jun 2020 at 15:41, Jonny Grant <jg@jguk.org> wrote:
>>
>> Hi Michael,
>>
>> Returning to an old topic, noticed strcpy man page is different from the POSIX spec with regards to "terminating NUL character" or "null-terminated" shouldn't man pages should follow POSIX style writing "NUL"?
>>
>> https://man7.org/linux/man-pages/man3/strcpy.3.html
>>
>> https://man7.org/linux/man-pages/man3/strcpy.3p.html
>>
>> https://pubs.opengroup.org/onlinepubs/9699919799/functions/strcpy.html
>>
>> Another function even has nul in the name
>> https://man7.org/linux/man-pages/man3/strchrnul.3.html
> 
> It's not so simple. In POSIX/SUS, you will find variously:
> 
> terminating NUL character
> terminating NUL
> terminating null character
> terminating null byte
> 
> There's even one instance of "terminating NULL character" (in
> <net/if.h>; I estimate it's a bug).
> 
> In the C standard (C11), "terminating null character" seems to be used
> exclusively, but as I understand the C standard [char == byte] by
> definition.
> 
> I've tried to consistently use "terminating null byte" across all
> pages in man-pages. See also the discussion in man-pages(7).

Hi Michael,

It is good you have made things consistent. It sounds like you can't make the POSIX man pages the same, as that comes from the POSIX spec right?

BTW,  net/if.h looks okay on my Ubuntu LTS, line 36 does have:
    char *if_name;		/* null terminated name: "eth0", ... */

Cheers, Jonny