[Bug 206176] Non-null-terminated arrays in descriptions of strn* and wcsn* functions

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=206176

            Bug ID: 206176
           Summary: Non-null-terminated arrays in descriptions of strn*
                    and wcsn* functions
           Product: Documentation
           Version: Latest
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Many People
          Priority: ---
         Component: Documentation
          Assignee: freebsd-doc at FreeBSD.org
          Reporter: cherepan at mccme.ru

The strn* and wcsn* functions take an argument limiting the size of processed
parts of arrays. The C standard cautiously and consistently talks about arrays
instead of strings in such cases and (hence) doesn't require arguments to be
null-terminated strings in all cases.

OTOH FreeBSD man pages don't make this distinction and don't usually make
remarks to that effect.

Take for example strcmp and strncmp. The description of strcmp in C11,
7.24.4.2p2:

"The strcmp function compares the string pointed to by s1 to the string pointed
to by s2."

It talks about "the string pointed to by s1" as expected.

Then, the description of strncmp -- C11, 7.24.4.4p2:

"The strncmp function compares not more than n characters (characters that
follow a null character are not compared) from the array pointed to by s1 to
the array pointed to by s2."

Here, it talks about "the array pointed to by s1" instead of strings.

In the next paragraph it talks about "the possibly null-terminated array
pointed to by s1" (please note "possibly").

The man page[1] for strncmp is silent on such details.

The same for strncat[2].

The question for non-C11 function like strncasecmp[3], strndup[4], strnstr[5]
is moot but IMHO it's better to be consistent with C11.

Implementations are mostly ok, only documentation is wrong.

[1]
https://svnweb.freebsd.org/base/head/lib/libc/string/strcmp.3?revision=251069&view=markup#l51
[2]
https://svnweb.freebsd.org/base/head/lib/libc/string/strcat.3?revision=262890&view=markup#l51
[3]
https://svnweb.freebsd.org/base/head/lib/libc/string/strcasecmp.3?revision=266865&view=markup#l55
[4]
https://svnweb.freebsd.org/base/head/lib/libc/string/strdup.3?revision=251069&view=markup#l63
[5]
https://svnweb.freebsd.org/base/head/lib/libc/string/strstr.3?revision=251069&view=markup#l77

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