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* Add a migration warning to the update release system and the elf programs documentation pages. This is just to add a papertrail from where the documentation originate in case of error during the migration process. * Improve the building nuttx with app out of source tree * Add new guide pages * Building uclibc++ * Custom app directories * Debugging ELF loadable modules * Multiple NSH sessions * NSH network link management * RAM & ROM disks * Reading CAN messages * Remove device drivers with NSH
84 lines
2.9 KiB
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84 lines
2.9 KiB
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=================
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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and is probably outdated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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