[PATCH v7] Implement strlcpy, strlcat [BZ #178]

[Alexander Cherepanov]

On 2016-01-06 00:05, Paul Eggert wrote:
> On 01/05/2016 11:14 AM, Alexander Cherepanov wrote:
>> Your first reading of POSIX seems quite reasonable to me. And that
>> reading conflicts with C11 so I reported it in
>> http://austingroupbugs.net/view.php?id=1020 .
>
> I was referring to the C11 semantics,

Ok. Then perhaps you are willing to remove the following piece from the 
snprintf description: "you should allocate at least @var{size} 
characters for the string @var{s}"[1]? (And maybe fix the use of 
xmalloc/xrealloc vs. results checks in the example there.)

More generally, the glibc manual describes many functions quite 
differently from C11 (e.g., I've filed bugs 19406 and 19407) and it's 
not clear what are the plans in this area.

[1] 
https://sourceware.org/git/?p=glibc.git;a=blob;f=manual/stdio.texi;h=0326f29eaecd6efa20dd397db095f755bffac495;hb=HEAD#l2474

> which POSIX defers to. In looking
> at that bug-report trail, it appears that the semantics of snprintf are
> controversial in this area. And rightly so, since C11 requires
> implementations to not diagnose troublesome application usage such as
> snprintf (buf, SIZE_MAX, ...).

Some call it troublesome, others consider SIZE_MAX a useful 
no-truncation-required value permitting to unify various code paths.

>> it boils down to the question which sources are considers
>> authoritative for describing strlcpy/strlcat?
>
> There aren't any. The BSD man pages do not agree, and their
> implementations do not agree. If we add strlcpy/strlcat, we will just
> need to use our best judgment to distinguish valid from buggy uses.

Ok, I see.

-- 
Alexander Cherepanov