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Install instructions for Unix Emulation

Software versions tested:

  • GCC 4.03 (Ubuntu Dapper) or GCC 4.1.2 (Ubuntu Feisty)
  • Ethernut 4.2.1
  • Mac OS X 10.5 (GCC 4.0)
  • Ethernut 4.4.1

Extract the source code of the Ethernut OS

  tar xvfj ethernut-4.2.1.tar.bz2

Enter the new folder and prepare the system for Unix emulation

  cd ethernut-4.2.1

Enter 5 for Unix Emulation

Fix some troublemakers

The 4.x version of the GCC compiler seems to be more sensitive to C-Code correctness than former versions. This results in error messages while trying to compile the NutOS directly.

Found issues in the sourcecode and fixes to make it run:

  • arch/unix/dev/ostimer.c

-> Ethernut 4.4 needs following line to be commented out (please explain it to me - seems useless on the one hand to declare function with attribute noreturn and on the other hand have the returntype void *)

//void *NutTimerEmulation(void *) __attribute__ ((noreturn));

missing return at the end of function NutTimerEmulation - solution:



at the end of this function

  • arch/unix/os/nutinit.c

-> Ethernut 4.4 needs following line to be commented out again

//void *NutInterruptEmulation(void *) __attribute__ ((noreturn));

another missing return at the end of function NutInterruptEmulation - solution:

again add


at the end of this function

  • the missing return at some functions error also appears at some

example applications. Eg. with many THREAD definitions it is necessary to add a - useless because actually never reached - return value to the end of concerning functions.

  • error messages at different device drivers with unsupported direct

hardware access - quick and dirty solution:

remove the following files (line beginning with SRCS = )from the makefile in the dev/ folder and prevent the compilation of the - in this environment - useless drivers

twbbif.c npl.c nplmmc.c sbimmc.c
  • some of the file system drivers cause trouble. So remove them out of the Makefile:

fs/Makefile :

#SRCS = pathops.c dirent.c fat.c uromfs.c pnutfs.c \
#       phatfs.c phatvol.c phatdir.c phatio.c \
#       phat12.c phat16.c phat32.c phatutil.c phatdbg.c

SRCS = uromfs.c 

Compile the sources and install the libraries

cd lib
make install

Adaptations at the example applications

By default hex-files for usage with mikrocontroller hardware are built. For Unix emulation this hardly makes sense so change the target definition of the application Makefile from .hex to .elf

TARG =  $(PROJ).elf

If the application directory is not inside the default example directory some Makefile variables of the application have to be adapted.

The Path /opt/ethernut-4.2.1_unixEmul/ has to be changed accordingly


top_srcdir = /opt/ethernut-4.2.1_unixEmul/
LIBDIR = /opt/ethernut-4.2.1_unixEmul/lib/gcc/unix
NUTPATH = /opt/ethernut-4.2.1_unixEmul/

Run the application

The built application can directly be executed


and should be debuggable this way more easily than with the embedded hardware.