Re: git: 5e6a2d6eb220 - main - Reapply: move libc++ from /usr/lib to /lib [add /usr/lib/libc++.so.1 -> ../../lib/libc++.so.1 ?]

On 2021-Dec-31, at 14:28, Mark Millard <marklmi@yahoo.com> wrote:

> On 2021-Dec-30, at 14:04, John Baldwin <jhb@freebsd.org> wrote:
> 
>> On 12/30/21 1:09 PM, Mark Millard wrote:
>>> On 2021-Dec-30, at 13:05, Mark Millard <marklmi@yahoo.com> wrote:
>>>> This asks a question in a different direction that my prior
>>>> reports about my builds vs. Cy's reported build.
>>>> 
>>>> Background:
>>>> 
>>>> /usr/obj/BUILDs/main-amd64-nodbg-clang/usr/main-src/amd64.amd64/tmp/usr/lib/libc++.so:GROUP ( /lib/libc++.so.1 /usr/lib/libcxxrt.so
>>>> and:
>>>> lrwxr-xr-x  1 root  wheel        23 Dec 29 13:17:01 2021 /usr/lib/libcxxrt.so -> ../../lib/libcxxrt.so.1
>>>> 
>>>> Why did libc++.so.1 not get a:
>>>> 
>>>> /usr/lib/libc++.so.1 -> ../../lib/libc++.so.1
>>> I forgot to remove the .1 on the left hand side:
>>> /usr/lib/libc++.so -> ../../lib/libc++.so.1
>> 
>> Because for libc++.so we don't just symlink to the current version of the library
>> (as we do for most other shared libraries) to tell the compiler what to link against
>> for -lc++, instead we use a linker script that tells the compiler to link against
>> both of those libraries when -lc++ is encountered.
> 
> A better identification of what looks odd to me is the
> path variations in:
> 
> # more /usr/lib/libc++.so

Another not great day on my part: That path alone makes
the mix of /lib/ and /usr/lib/ use involved, given the
reference to /lib/libc++.so.1 . That would still be true
if the other path had been /lib/libcxxrt.so .

I guess I've just not figured out what specific, detailed
issue(s) the move to /lib/libc++.so.1 covers vs. not,
given the /usr/lib/libc++.so and /usr/lib/libcxxrt.so
paths.

I'm not using anything with /usr/lib/ being on a different
file system than /lib so I'll definitely not observe any
problems. And it might be a waste to try to clear my
confusions at this point, given how the day is going.

> /* $FreeBSD$ */
> GROUP ( /lib/libc++.so.1 /usr/lib/libcxxrt.so )
> 
> So /usr/lib/ still has to be available (so, possibly, mounted)
> for C++ because of the /usr/lib/libcxxrt.so reference? If so,
> why the move of libc++.so.1 to /lib/ ?
> 
>> I have finally reproduced Cy's build error locally and am testing my fix.  If it
>> works I'll commit it.
>> 
> 


===
Mark Millard
marklmi at yahoo.com