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f6ecf80ebb
The documentation grew one page at a time, so the tree follows the
history of who wrote what and not the shape of NuttX. Scheduling is
spread over three places, a driver page can sit above the subsystem
that owns it, and the front page lists everything at the same level.
That is a lot to face when all you want to know is where the scheduler
lives.
This change files every page under the code it describes. It is a move,
not a rewrite: outside the ten pages named below, every page keeps the
text that is already in master, and no page's text is deleted.
What it does:
* Groups the table of contents into nine chapters.
* Moves the OS subsystems under os/: scheduling, memory, drivers,
filesystem, networking, IPC, interrupts, libs, time.
* Renames the platform pages to the names the source tree uses, and
derives their tags from the tree instead of by hand.
* Splits guides/ by subject.
* Adds Documentation/redirects.py, with a rule for every page that left
its old path, so old URLs keep working. The redirect page also carries
a link's #anchor across to the new page.
Ten pages have text that is new or rewritten. Nine of them are the
landing page of a chapter, which has to exist for the new structure:
index the front page
os/index OS Design
os/scheduling/index Scheduling
os/interrupts/index Interrupts
os/ipc/index IPC
os/time/index Time and timers
about/index About
developing/index Developing NuttX
ReleaseNotes/index Release notes
The tenth is os/libs/libbuiltin, the only page here with technical
content: libs/libbuiltin/ had no page at all. Five SVG diagrams come
with these pages, hand-written XML with no editor metadata.
Nothing outside Documentation/ is touched.
How it was checked:
* Sphinx builds with -W: no warnings, and no document left outside a
toctree.
* A script, offered in the PR, proves the narrow claim this rests on.
For every page outside the ten named above it erases what a move
touches -- link target, path, tag line, toctree block, table border --
from the whole old text and the whole new text, and requires the two
to be byte for byte identical. It also requires every sentence of a
deleted page to turn up somewhere, and every page that left its old
path to have a redirect, from a URL that existed, to where its content
went. It exits non-zero and names the page if any of that is not true,
and it tests added pages too, so forgetting to declare one cannot make
it pass.
* An independent audit checked 133 factual claims on these ten pages
against the tree, one shell command per claim: 130 confirmed, 1
refuted and fixed here, 2 not checkable.
* tools/checkpatch.sh is clean over the range.
The diff is large because moving a page changes every link that points
to it. Most of it is pure renames, and board pages that gained one tag
line.
Assisted-by: Claude:claude-opus-5
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2.9 KiB
ReStructuredText
84 lines
2.9 KiB
ReStructuredText
=================
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Building uClibc++
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=================
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.. warning::
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Migrated from:
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https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=139629550
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and is probably outdated
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A version of `uClibc++ <http://cxx.uclibc.org/>`_ has been ported to NuttX and is available in the NuttX
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uClibc++ GIT repository at `Bitbucket.org <https://bitbucket.org/nuttx/uclibc/>`_ . This version of uClibc++ was
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adapted for NuttX by the RGMP team.
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This custom version of uClibc++ resides in the NuttX repository at:
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https://bitbucket.org/nuttx/uclibc/
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rather than in the main NuttX source tree, due to licensing issues: NuttX is
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licensed under the permissive, modified BSD License; uClibc++, on the other
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hand, is licensed under the stricter GNU LGPL Version 3 license.
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General build instructions are available in the uClibc++ `README.txt <https://bitbucket.org/nuttx/uclibc/src/master/README.txt>`_
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file. Those instructions are not repeated here. This page documents specific
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issues encountered when building this NuttX version of uClibc++ and how they
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are resolved.
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Undefined Reference to ``_impure_ptr``
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======================================
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**Problem**
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When building uClibc++, you may encounter an undefined reference to
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``_impure_ptr`` similar to:
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.. code-block:: none
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LD: nuttx
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.../arm-none-eabi/lib/armv7e-m\libsupc++.a(vterminate.o): In function
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`__gnu_cxx::__verbose_terminate_handler()`:
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vterminate.cc:(.text._ZN9__gnu_cxx27__verbose_terminate_handlerEv+0xfc):
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undefined reference to `_impure_ptr'
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**Solution**
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A definitive, elegant solution is not known, but the following workaround has
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proven to work:
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1. Locate the directory where you can find ``libsupc++``:
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.. code-block:: console
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arm-none-eabi-gcc -mcpu=cortex-m4 -mthumb -print-file-name=libsupc++.a
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2. Go to that directory and save a copy of ``vterminate.o`` (in case you need
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it later):
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.. code-block:: console
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cd <the-directory-containing-libsupc++.a>
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arm-none-eabi-ar.exe -x libsupc++.a vterminate.o
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3. Remove ``vterminate.o`` from the library. At build time, the uClibc++
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package will provide a usable replacement:
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.. code-block:: console
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arm-none-eabi-ar.exe -d libsupc++.a vterminate.o
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4. At this point, NuttX should link with no problem. If you ever want to
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restore the original ``vterminate.o`` to ``libsupc++.a``, you can do so
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by running:
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.. code-block:: console
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arm-none-eabi-ar.exe rcs libsupc++.a vterminate.o
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After removing ``vterminate.o`` from the standard library, the
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uClibc++-provided ``vterminate.o`` becomes the active implementation and
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prevents references to ``_impure_ptr`` from arising during linkage.
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.. note::
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Always exercise caution when modifying toolchain libraries. This
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workaround is known to be effective but it replaces standard library
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objects, which may have side effects in other toolchain usage scenarios.
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