looking for tree to use for gr-iio and gnuradio 3.9

[Chris Gorman]

Hello All,

I am trying to migrate gr-iio -b maint-3.8 to gnuradio 3.9 with
pybind11.  I have, I think, got most of it working.

My latest hurdle is at
https://wiki.gnuradio.org/index.php/GNU_Radio_3.9_OOT_Module_Porting_Guide.
Step 8. Though not necessary, boost::bind instances for message port
handlers can be replaced with lambda functions for performance and
simplicity as well as consistency with the in-tree modules.

My main reason for looking to do this is I get an error during my
build related to boost::bind.

[ 25%] Building CXX object lib/CMakeFiles/gnuradio-iio.dir/attr_sink_impl.cc.o
cd /home/chris/src/iio/gr-iio/build/lib && /usr/bin/c++
-DBOOST_ALL_NO_LIB -DBOOST_FILESYSTEM_DYN_LINK
-DBOOST_PROGRAM_OPTIONS_DYN_LINK -DBOOST_REGEX_DYN_LINK
-DBOOST_SYSTEM_DYN_LINK -DBOOST_THREAD_DYN_LINK -DFFTW3F_THREADS
-DGR_CTRLPORT -Dgnuradio_iio_EXPORTS
-I/home/chris/src/iio/gr-iio/lib/../include
-I/home/chris/src/iio/gr-iio/build/lib -isystem /usr/include/python3.8
-isystem /usr/lib/python3.8/site-packages/numpy/core/include -isystem
/opt/gnuradio/include -O3 -DNDEBUG -fPIC   -fvisibility=hidden
-std=gnu++11 -o CMakeFiles/gnuradio-iio.dir/attr_sink_impl.cc.o -c
/home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc
/home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc: In constructor
‘gr::iio::attr_sink_impl::attr_sink_impl(const string&, const string&,
const string&, int, bool, bool)’:
/home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc:92:92: error: ‘_1’
was not declared in this scope
   92 | ::mp("attr"), boost::bind(&attr_sink_impl::write_attribute, this, _1));
      |                                                                   ^~

/home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc:92:92: note:
suggested alternatives:
In file included from /usr/include/boost/mpl/aux_/include_preprocessed.hpp:37,
                 from /usr/include/boost/mpl/placeholders.hpp:43,
                 from /usr/include/boost/iterator/iterator_categories.hpp:16,
                 from /usr/include/boost/iterator/iterator_facade.hpp:13,
                 from /usr/include/boost/filesystem/path.hpp:29,
                 from /usr/include/boost/filesystem.hpp:16,
                 from /opt/gnuradio/include/gnuradio/logger.h:36,
                 from /opt/gnuradio/include/gnuradio/basic_block.h:16,
                 from /opt/gnuradio/include/gnuradio/block.h:15,
                 from
/home/chris/src/iio/gr-iio/lib/../include/iio/attr_sink.h:27,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.h:26,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc:27:
/usr/include/boost/mpl/aux_/preprocessed/gcc/placeholders.hpp:29:16:
note:   ‘mpl_::_1’
   29 | typedef arg<1> _1;
      |                ^~
In file included from /usr/include/boost/system/error_code.hpp:19,
                 from /usr/include/boost/filesystem/path_traits.hpp:22,
                 from /usr/include/boost/filesystem/path.hpp:26,
                 from /usr/include/boost/filesystem.hpp:16,
                 from /opt/gnuradio/include/gnuradio/logger.h:36,
                 from /opt/gnuradio/include/gnuradio/basic_block.h:16,
                 from /opt/gnuradio/include/gnuradio/block.h:15,
                 from
/home/chris/src/iio/gr-iio/lib/../include/iio/attr_sink.h:27,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.h:26,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc:27:
/usr/include/c++/10.2.0/functional:221:34: note:   ‘std::placeholders::_1’
  221 |     extern const _Placeholder<1> _1;
      |                                  ^~
In file included from /usr/include/boost/mpl/aux_/include_preprocessed.hpp:37,
                 from /usr/include/boost/mpl/placeholders.hpp:43,
                 from /usr/include/boost/iterator/iterator_categories.hpp:16,
                 from /usr/include/boost/iterator/iterator_facade.hpp:13,
                 from /usr/include/boost/filesystem/path.hpp:29,
                 from /usr/include/boost/filesystem.hpp:16,
                 from /opt/gnuradio/include/gnuradio/logger.h:36,
                 from /opt/gnuradio/include/gnuradio/basic_block.h:16,
                 from /opt/gnuradio/include/gnuradio/block.h:15,
                 from
/home/chris/src/iio/gr-iio/lib/../include/iio/attr_sink.h:27,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.h:26,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc:27:
/usr/include/boost/mpl/aux_/preprocessed/gcc/placeholders.hpp:29:16:
note:   ‘mpl_::_1’
   29 | typedef arg<1> _1;
      |                ^~
In file included from /usr/include/boost/bind/bind.hpp:2356,
                 from /usr/include/boost/thread/detail/thread.hpp:33,
                 from /usr/include/boost/thread/thread_only.hpp:22,
                 from /usr/include/boost/thread/thread.hpp:12,
                 from /usr/include/boost/thread.hpp:13,
                 from /opt/gnuradio/include/gnuradio/logger.h:38,
                 from /opt/gnuradio/include/gnuradio/basic_block.h:16,
                 from /opt/gnuradio/include/gnuradio/block.h:15,
                 from
/home/chris/src/iio/gr-iio/lib/../include/iio/attr_sink.h:27,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.h:26,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc:27:
/usr/include/boost/bind/placeholders.hpp:46:38: note:
‘boost::placeholders::_1’
   46 | BOOST_STATIC_CONSTEXPR boost::arg<1> _1;
      |                                      ^~
In file included from /usr/include/boost/mpl/aux_/include_preprocessed.hpp:37,
                 from /usr/include/boost/mpl/placeholders.hpp:43,
                 from /usr/include/boost/iterator/iterator_categories.hpp:16,
                 from /usr/include/boost/iterator/iterator_facade.hpp:13,
                 from /usr/include/boost/filesystem/path.hpp:29,
                 from /usr/include/boost/filesystem.hpp:16,
                 from /opt/gnuradio/include/gnuradio/logger.h:36,
                 from /opt/gnuradio/include/gnuradio/basic_block.h:16,
                 from /opt/gnuradio/include/gnuradio/block.h:15,
                 from
/home/chris/src/iio/gr-iio/lib/../include/iio/attr_sink.h:27,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.h:26,
                 from /home/chris/src/iio/gr-iio/lib/attr_sink_impl.cc:27:
/usr/include/boost/mpl/aux_/preprocessed/gcc/placeholders.hpp:29:16:
note:   ‘mpl_::_1’
   29 | typedef arg<1> _1;
      |                ^~
make[2]: *** [lib/CMakeFiles/gnuradio-iio.dir/build.make:197:
lib/CMakeFiles/gnuradio-iio.dir/attr_sink_impl.cc.o] Error 1
make[2]: Leaving directory '/home/chris/src/iio/gr-iio/build'
make[1]: *** [CMakeFiles/Makefile2:267:
lib/CMakeFiles/gnuradio-iio.dir/all] Error 2
make[1]: Leaving directory '/home/chris/src/iio/gr-iio/build'
make: *** [Makefile:149: all] Error 2

A few questions.  Does anyone know which, if any, solution proposed by
the compiler, I should pursue? Is there an easy fix with lambda
functions?

Finally, I am wondering if there is a better branch than maint-3.8 to
use for migrating gr-iio?

Thanks in advance,

Chris