[PATCH] Fix up LD_* vars behaviour

[Michael Kerrisk]

On Sat, Apr 14, 2012 at 10:56 AM, Nix <nix@esperi.org.uk> wrote:
> On 13 Apr 2012, Michael Kerrisk told this:
>
>> Hello Nix,
>>
>> On Fri, Apr 13, 2012 at 7:34 PM, Nix <nix@esperi.org.uk> wrote:
>>> On 13 Apr 2012, Carlos O'Donell stated:
>>>> (1) Official standards like http://pubs.opengroup.org/onlinepubs/009695399/
>>>> - Information about portability is very good.
>>>> - Unfortunately they do not document glibc specific information.
>>>>
>>>> (2) The GNU C Library manual http://www.gnu.org/software/libc/manual/
>>>> - Traditional manual available in many formats.
>>>>
>>>> (3) The man-pages project
>>>> http://man7.org/linux/man-pages/dir_all_alphabetic.html
>>>> - Detailed information per interface in man format.
>>>>
>>>> Each of (1), (2) and (3) offers our users choice in how they want to
>>>> view the APIs.
>>>
>>> If it wasn't for the GPL/GFDL licensing difference, it would seem
>>> reasonable to use the manpages for the things not documented in glibc as
>>> a source for glibc documentation -- the most notable is that (1), (2)
>>
>> Did you mean "(1), (3)"?
>
> *ouch* yes. I'm typoing everywhere today: obviously I should just
> retreat into a shell and pull it over me until I can type straight.
>
> (I checked that twice, too.)

;-)

>>                          (Note by the way, that man-pages coverage of
>> the pthreads API is far from complete. There's a good set of pages for
>> some of the basic APIs, but many others are as yet absent. See the
>> last part of http://www.kernel.org/doc/man-pages/missing_pages.html)
>
> Now *that* page is worth keeping track of.

Note though that is a hand-made creation, and not 100% complete or
accurate (but probably > 90% so).

> (if I ever learn enough troff that I can do more than cargo-cult man
> pages, I might try writing some of those missing bits.)
>
>>> and Michael's book all document pthreads, while the glibc docs don't
>>> mention them. (The book's documentation is particularly good: I don't
>>> feel like I truly understood pthreads until I read it.)
>>
>> Thanks, that's nice to hear. I sweated some blood over trying to make
>> some pieces clear. (Thread-specific data springs to mind.)
>
> Well, your effort was not wasted. I can't say I left it liking pthreads
> to any great degree, but at least I understood it enough to dislike it
> for good reasons (and to fix bugs in threaded programs). TLPI has
> supplanted APUE on my shelves now. Before it was published I had
> despaired of anyone writing anything as clear and useful as APUE ever
> again, so thank you!

You're very welcome. Any comparison with APUE is always great praise.
WRS was a genius of a write; I'm standing on the shoulders of giants,
and so on.

>>> But the licensing difference probably means that glibc needs to write
>>> docs for pthreads from scratch :(
>>
>> Above, you mentioned the "GPL/GFDL licensing difference", and here you
>> mention licensing difference again. I'm not sure what you're alluding
>> to here.
>
> Well, glibc's documentation is GFDL. man-pages is (mostly?) not. And
> man-pages's pages are mostly written by multiple people. So direct
> transfer of text from man-pages into the glibc documentation seems
> likely to be difficult at best.

There are no GFDL pages in man-pages. Once upon a time there were one
or two. These were explicitly removed/rewritten to make life easier
for Debian.

>> 508 pages under what I call the "verbatim license"
>> (http://www.kernel.org/doc/man-pages/licenses.html#verbatim I don't
>> know the origin of the license, or whether it has another name, but
>> it's the license I tend to favor, and Andries likewise seemed to favor
>> it.)
>
> At first sight, this looks GFDL-compatible, but I'm not a lawyer nor
> have I ever played one even in a dream, let alone on TV. If it *is*
> GFDL-compatible, then one-way copying into glibc's info pages may be
> possible (if the formatting and stylistic differences between man-pages
> and glibc's documentation are easy enough to compensate for for that to
> be worthwhile, of course).
>
>> 325 pages licensed as GPL--specifically GPLv2, either explicitly, or
>> implicitly (by implication of when the license note was placed).
>
> Probably much harder to copy into glibc :(

See my other reply to Carlos. I suggest that the way forward is not to
duplicated content or effort in man-pages and the glibc manual. Aside
from the effort, there's all the other problems (e.g., sync issues)
that result when one copies documentation between two places.

Cheers,

Michael