PX4-Autopilot/misc/uClibc++

misc/uClib++ README

^^^^^^^^^^^^^^^^^^^



This directory contains a version of the uClibc++ C++ library.  This code

originates from http://cxx.uclibc.org/ and has been adapted for NuttX by the

RGMP team (http://rgmp.sourceforge.net/wiki/index.php/Main_Page).



uClibc++ resides in the misc/ directory rather than in the main NuttX source

tree due to licensing issues:  NuttX is licensed under the permissiv

 modified BSD License; uClibc, on the other hand, islicensed under the

 stricter GNU LGPL Version 3 license.



Installation of uClibc++

^^^^^^^^^^^^^^^^^^^^^^^^



If you wish to use uClibc++ with NuttX, you will be required to comply with

the licensing requires of the GNU LGPL Version 3 license.  A simple

installation script is provided at misc/uClibc++/install.sh that can be used

to install the uClibc++ components into the NuttX source tree.



The install script takes only a single arguement: The path to the nuttx

directory.  If your directory structure is the same as the SVN structure

(with misc/ and nuttx/ at the same level), then uClibc++ can be installed

using this command executed from the misc/uClibc++ directory:



  ./install.sh ../../nuttx



If you run the install.sh like this, then it will (1) make sure you

understand that you have tainted the NuttX BSD license with LGPLv3, and (2)

copy the uClibc++ sources files into nuttx/libxx/uClibc++, include/, and

include/uClibc++.



Make.defs File Changes

^^^^^^^^^^^^^^^^^^^^^^



The new files that appear in nuttx/include/uClibc++ must be include-able

as system header files.  So you will need to add 'isystem $(TOPDIR)/include/uClibc++'

to the ARCHINCLUDESXX definition in the NuttX Make.defs file, perhap like:



  -ARCHINCLUDESXX = -I. -isystem $(TOPDIR)/include -isystem $(TOPDIR)/include/cxx

  +ARCHINCLUDESXX = -I. -isystem $(TOPDIR)/include -isystem $(TOPDIR)/include/cxx -isystem $(TOPDIR)/include/uClibc++



And, of course, you no long need to suppress exceptions or run-time typing:



  -ARCHCPUFLAGSXX = -fno-builtin -fno-exceptions -fno-rtti

  +ARCHCPUFLAGSXX = -fno-builtin



Building NuttX with uClibc++

^^^^^^^^^^^^^^^^^^^^^^^^^^^^



After installing uClibc++ in this way, no additional steps should be

required to build NuttX with the uClibc++ library incorporated:



  $ cd ../../nuttx

  $ . ./setenv.sh

  $ make



Here is how it works:



There is a new file called Make.defs in misc/uClibc/libxx/uClibc++. After

installation, it will reside at nuttx/libxx/uClibc++. The

nuttx/libxx/Makefile will (conditionally) include this Make.defs file:



-include uClibc++/Make.defs



This Make.defs file, if present, will add the uClibc++ source files to the

build, add the uClibc++ subdirectory to the dependency list, and add the

uClibc++ subdirectory to the VPATH. That should, in principle, be all it

takes.



Dependencies

^^^^^^^^^^^^



In order to build libxx (and hence libxx/uClibc++), CONFIG_HAVE_CXX must be

defined in your NuttX configuration file.



The C++ runtime support is provided by GCC libgcc_eh.a and libsupc++.a

libraries.



RGMP

^^^^



The target platform is RGMP X86, it is also updated for TLS support which is

needed by these two libraries. So application can also use TLS on RGMP NuttX

port.



Command to compile and install RGMP:



  $ make

  $ make install

  $ /usr/rgmp/setup

  $ exit



Command to compile and run NUTTX:



  $ cd nuttx/tools

  $ ./configure rgmp/x86/cxxtest

  $ cd ..

  $ make

  $ rgmp_run