README.txt

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

Strange Path Problems
---------------------

  If you see strange behavior when building under Cygwin then you may have
  a problem with your PATH variable.  For example, if you see failures to
  locate files that are clearly present, that may mean that you are using
  the wrong version of a tool.  For example, you may not be using Cygwin's
  'make' program at /usr/bin/make.  Try:

    $ which make
    /usr/bin/make

  When you install some toolchains (such as Yargarto or CodeSourcery tools),
  they may modify your PATH variable to include a path to their binaries.
  At that location, they make have GNUWin32 versions of the tools.  So you
  might actually be using a version of make that does not understand Cygwin
  paths.

  The solution is either:

  1. Edit your PATH to remove the path to the GNUWin32 tools, or
  2. Put /usr/local/bin, /usr/bin, and /bin at the front of your path:

     $ export PATH=/usr/local/bin:/usr/bin:/bin:$PATH

Window Native Toolchain Issues
------------------------------

  There are many popular Windows native toolchains that may be used with NuttX.
  Examples include CodeSourcery (for Windows), devkitARM, and several vendor-
  provied toolchains.  There are several limitations with using a and Windows
  based toolchain in a Cygwin environment.  The three biggest are:

  1. The Windows toolchain cannot follow Cygwin paths.  Path conversions are
     performed automatically in the Cygwin makefiles using the 'cygpath' utility
     but you might easily find some new path problems.  If so, check out 'cygpath -w'

  2. Windows toolchains cannot follow Cygwin symbolic links.  Many symbolic links
     are used in Nuttx (e.g., include/arch).  The make system works around these
     problems for the Windows tools by copying directories instead of linking them.
     But this can also cause some confusion for you:  For example, you may edit
     a file in a "linked" directory and find that your changes had no effect.
     That is because you are building the copy of the file in the "fake" symbolic
     directory.  If you use a Windows toolchain, you should get in the habit of
     making like this:

       make clean_context all

     An alias in your .bashrc file might make that less painful.  The rebuild
     is not a long as you might think because there is no dependency checking
     if you are using a native Windows toolchain.  That bring us to #3:

  3. Dependencies are not made when using Windows versions of the GCC on a POSIX
     platform (i.e., Cygwin).  This is because the dependencies are generated
     using Windows paths which do not work with the Cygwin make.

       MKDEP                = $(TOPDIR)/tools/mknulldeps.sh

     If you are building natively on Windows, then no such conflict exists
     and the best selection is:

       MKDEP                = $(TOPDIR)/tools/mkdeps.exe

General Pre-built Toolchain Issues

  To continue with the list of "Window Native Toolchain Issues" we can add
  the following.  These, however, are really just issues that you will have
  if you use any pre-built toolchain (vs. building the NuttX toolchain from
  the NuttX buildroot package):

  There may be incompatibilities with header files, libraries, and compiler
  built-in functions at detailed below.  For the most part, these issues
  are handled in the existing make logic.  But if you are breaking new ground,
  then you may encounter these:

  4. Header Files.  Most pre-built toolchains will build with a foreign C
     library (usually newlib, but maybe uClibc or glibc if you are using a
     Linux toolchain).  This means that the header files from the foreign
     C library will be built into the toolchain.  So if you "include <stdio.h>",
     you will get the stdio.h from the incompatible, foreign C library and
     not the nuttx stdio.h (at nuttx/include/stdio.h) that you wanted.

     This can cause really confusion in the builds and you must always be
     sure the -nostdinc is included in the CFLAGS.  That will assure that
     you take the include files only from

  5. Libraries.  What was said above header files applies to libraries.
     You do not want to include code from the libraries of any foreign
     C libraries built into your toolchain.  If this happens you will get
     perplexing errors about undefined symbols.  To avoid these errors,
     you will need to add -nostdlib to your CFLAGS flags to assure that
     you only take code from the NuttX libraries.

     This, however, may causes other issues for libraries in the toolchain
     that you do want (like libgcc.a or libm.a).  These are special-cased
     in most Makefiles, but you could still run into issues of missing
     libraries.

  6. Built-Ins.  Some compilers target a particular operating system.
     Many people would, for example, like to use the same toolchain to
     develop Linux and NuttX software.  Compilers built for other
     operating systems may generate incompatible built-in logic and,
     for this reason, -fno-builtin should also be included in your
     C flags

  And finally you may not be able to use NXFLAT.

  7. NXFLAT. If you use a pre-built toolchain, you will lose all support
     for NXFLAT.  NXFLAT is a binary format described in
     Documentation/NuttXNxFlat.html.  It may be possible to build
     standalone versions of the NXFLAT tools; there are a few examples
     of this in the buildroot repository at https://bitbucket.org/nuttx/buildroot
     However, it is possible that there could be interoperability issues
     with your toolchain since they will be using different versions of
     binutils and possibly different ABIs.

Building Original Linux Boards in Cygwin

  Some default board configurations are set to build under Linux and others
  to build under Windows with Cygwin.  Various default toolchains may also
  be used in each configuration.  It is possible to change the default
  setup.  Here, for example, is what you must do in order to compile a
  default Linux configuration in the Cygwin environment using the
  CodeSourceery for Windows toolchain.  After instantiating a "canned"
  NuttX configuration, run the target 'menuconfig' and set the following
  items:

    Build Setup->Build Host Platform->Windows
    Build Setup->Windows Build Environment->Cygwin
    System Type->Toolchain Selection->CodeSourcery GNU Toolchain under Windows

  In Windows 7 it may be required to open the Cygwin shell as Administrator
  ("Run As" option, right button) you find errors like "Permission denied".

Recovering from Bad Configurations

  Many people make the mistake of configuring NuttX with the "canned"
  configuration and then just typing 'make' with disastrous consequences;
  the build may fail with mysterious, uninterpretable, and irrecoverable
  build errors.  If, for example, you do this with an unmodified Linux
  configuration in a Windows/Cgwin environment, you will corrupt the
  build environment.  The environment will be corrupted because of POSIX vs
  Windows path issues and with issues related to symbolic links.  If you
  make the mistake of doing this, the easiest way to recover is to just
  start over: Do 'make distclean' to remove every trace of the corrupted
  configuration, reconfigure from scratch, and make certain that the set
  the configuration correctly for your platform before attempting to make
  again.

  Just fixing the configuration file after you have instantiated the bad
  configuration with 'make' is not enough.

DOCUMENTATION
^^^^^^^^^^^^^

Additional information can be found in the Documentation/ directory and
also in README files that are scattered throughout the source tree.  The
documentation is in HTML and can be access by loading the following file
into your Web browser:

  Documentation/index.html

NuttX documentation is also available online at http://www.nuttx.org.

Below is a guide to the available README files in the NuttX source tree:

nuttx
 |
 |- arch/
 |   |
 |   |- arm/
 |   |   `- src
 |   |       `- lpc214x/README.txt
 |   |- sh/
 |   |   |- include/
 |   |   |   `-README.txt
 |   |   |- src/
 |   |   |   `-README.txt
 |   |- x86/
 |   |   |- include/
 |   |   |   `-README.txt
 |   |   `- src/
 |   |       `-README.txt
 |   `- z80/
 |   |   `- src/
 |   |       |- z80/README.txt
 |   |       `- z180/README.txt, z180_mmu.txt
 |   `- README.txt
 |- audio/
 |   `-README.txt
 |- binfmt/
 |   `-libpcode/
 |       `-README.txt
 |- configs/
 |   |- amber/
 |   |   `- README.txt
 |   |- arduino-due/
 |   |   `- README.txt
 |   |- avr32dev1/
 |   |   `- README.txt
 |   |- c5471evm/
 |   |   `- README.txt
 |   |- cc3200-launchpad/
 |   |   `- README.txt
 |   |- cloudctrl
 |   |   `- README.txt
 |   |- compal_e86
 |   |   `- README.txt
 |   |- compal_e88
 |   |   `- README.txt
 |   |- compal_e99
 |   |   `- README.txt
 |   |- demo0s12ne64/
 |   |   `- README.txt
 |   |- dk-tm4c129x/
 |   |   `- README.txt
 |   |- ea3131/
 |   |   `- README.txt
 |   |- ea3152/
 |   |   `- README.txt
 |   |- eagle100/
 |   |   `- README.txt
 |   |- efm32-g8xx-stk/
 |   |   `- README.txt
 |   |- efm32gg-stk3700/
 |   |   `- README.txt
 |   |- ekk-lm3s9b96/
 |   |   `- README.txt
 |   |- ez80f910200kitg/
 |   |   |- ostest/README.txt
 |   |   `- README.txt
 |   |- ez80f910200zco/
 |   |   |- dhcpd/README.txt
 |   |   |- httpd/README.txt
 |   |   |- nettest/README.txt
 |   |   |- nsh/README.txt
 |   |   |- ostest/README.txt
 |   |   |- poll/README.txt
 |   |   `- README.txt
 |   |- fire-stm32v2/
 |   |   `- README.txt
 |   |- freedom-kl25z/
 |   |   `- README.txt
 |   |- freedom-kl26z/
 |   |   `- README.txt
 |   |- hymini-stm32v/
 |   |   `- README.txt
 |   |- kwikstik-k40/
 |   |   `- README.txt
 |   |- lincoln60/
 |   |   `- README.txt
 |   |- lm3s6432-s2e/
 |   |   `- README.txt
 |   |- lm3s6965-ek/
 |   |   `- README.txt
 |   |- lm3s8962-ek/
 |   |   `- README.txt
 |   |- lpc4330-xplorer/
 |   |   `- README.txt
 |   |- lpc4357-evb/
 |   |   `- README.txt
 |   |- lpcxpresso-lpc1115/
 |   |   `- README.txt
 |   |- lpcxpresso-lpc1768/
 |   |   `- README.txt
 |   |- maple/
 |   |   `- README.txt
 |   |- mbed/
 |   |   `- README.txt
 |   |- mcu123-lpc214x/
 |   |   `- README.txt
 |   |- micropendous3/
 |   |   `- README.txt
 |   |- mikroe-stm32f/
 |   |   `- README.txt
 |   |- mirtoo/
 |   |   `- README.txt
 |   |- mt-db-x3/
 |   |   `- README.txt
 |   |- moteino-mega/
 |   |   `- README.txt
 |   |- mx1ads/
 |   |   `- README.txt
 |   |- ne63badge/
 |   |   `- README.txt
 |   |- ntosd-dm320/
 |   |   |- doc/README.txt
 |   |   `- README.txt
 |   |- nucleo-f4x1re/
 |   |   `- README.txt
 |   |- nucleus2g/
 |   |   `- README.txt
 |   |- nutiny-nuc120/
 |   |   `- README.txt
 |   |- olimex-efm32g880f129-stk/
 |   |   `- README.txt
 |   |- olimex-lpc1766stk/
 |   |   `- README.txt
 |   |- olimex-lpc2378/
 |   |   `- README.txt
 |   |- olimex-lpc-h3131/
 |   |   `- README.txt
 |   |- olimex-stm32-h405/
 |   |   `- README.txt
 |   |- olimex-stm32-p107/
 |   |   `- README.txt
 |   |- olimex-stm32-p207/
 |   |   `- README.txt
 |   |- olimex-strp711/
 |   |   `- README.txt
 |   |- open1788/
 |   |   `- README.txt
 |   |- p112/
 |   |   `- README.txt
 |   |- pcblogic-pic32mx/
 |   |   `- README.txt
 |   |- pcduino-a10/
 |   |   `- README.txt
 |   |- pic32mx-starterkit/
 |   |   `- README.txt
 |   |- pic32mx7mmb/
 |   |   `- README.txt
 |   |- pic32mz-starterkit/
 |   |   `- README.txt
 |   |- pirelli_dpl10/
 |   |   `- README.txt
 |   |- qemu-i486/
 |   |   `- README.txt
 |   |- rgmp/
 |   |   `- README.txt
 |   |- sama5d3x-ek/
 |   |   `- README.txt
 |   |- sama5d3-xplained/
 |   |   `- README.txt
 |   |- sama5d4-ek/
 |   |   `- README.txt
 |   |- samd20-xplained/
 |   |   `- README.txt
 |   |- samd21-xplained/
 |   |   `- README.txt
 |   |- saml21-xplained/
 |   |   `- README.txt
 |   |- sam3u-ek/
 |   |   `- README.txt
 |   |- sam4e-ek/
 |   |   `- README.txt
 |   |- sam4l-xplained/
 |   |   `- README.txt
 |   |- sam4s-xplained/
 |   |   `- README.txt
 |   |- sam4s-xplained-pro/
 |   |   `- README.txt
 |   |- samv7i-xult/
 |   |   `- README.txt
 |   |- sim/
 |   |   `- README.txt
 |   |- shenzhou/
 |   |   `- README.txt
 |   |- skp16c26/
 |   |   `- README.txt
 |   |- spark/
 |   |   `- README.txt
 |   |- stm3210e-eval/
 |   |   |- RIDE/README.txt
 |   |   `- README.txt
 |   |- stm3220g-eval/
 |   |   `- README.txt
 |   |- stm3240g-eval/
 |   |   `- README.txt
 |   |- stm32_tiny/
 |   |   `- README.txt
 |   |- stm32f3discovery/
 |   |   `- README.txt
 |   |- stm32f4discovery/
 |   |   `- README.txt
 |   |- stm32f429i-disco/
 |   |   |- ltdc/README.txt
 |   |   `- README.txt
 |   |- stm32ldiscovery/
 |   |   `- README.txt
 |   |- stm32vldiscovery/
 |   |   `- README.txt
 |   |- sure-pic32mx/
 |   |   `- README.txt
 |   |- teensy-2.0/
 |   |   `- README.txt
 |   |- teensy-3.x/
 |   |   `- README.txt
 |   |- teensy-lc/
 |   |   `- README.txt
 |   |- tm4c123g-launchpad/
 |   |   `- README.txt
 |   |- tm4c1294-launchpad/
 |   |   `- README.txt
 |   |- twr-k60n512/
 |   |   `- README.txt
 |   |- ubw32/
 |   |   `- README.txt
 |   |- us7032evb1/
 |   |   `- README.txt
 |   |- viewtool-stm32f107/
 |   |   `- README.txt
 |   |- vsn/
 |   |   |- src/README.txt
 |   |   `- README.txt
 |   |- xtrs/
 |   |   `- README.txt
 |   |- z16f2800100zcog/
 |   |   |- ostest/README.txt
 |   |   |- pashello/README.txt
 |   |   `- README.txt
 |   |- z80sim/
 |   |   `- README.txt
 |   |- z8encore000zco/
 |   |   |- ostest/README.txt
 |   |   `- README.txt
 |   |- z8f64200100kit/
 |   |   |- ostest/README.txt
 |   |   `- README.txt
 |   |- zkit-arm-1769/
 |   |   `- README.txt
 |   |- zp214xpa/
 |   |   `- README.txt
 |   `- README.txt
 |- drivers/
 |   |- eeprom/
 |   |   `- README.txt
 |   |- lcd/
 |   |   `- README.txt
 |   |- mtd/
 |   |   `- README.txt
 |   |- sensors/
 |   |   `- README.txt
 |   |- sercomm/
 |   |   `- README.txt
 |   |- syslog/
 |   |   `- README.txt
 |   `- README.txt
 |- fs/
 |   |- binfs/
 |   |   `- README.txt
 |   |- mmap/
 |   |   `- README.txt
 |   |- nxffs/
 |   |   `- README.txt
 |   |- smartfs/
 |   |   `- README.txt
 |   |- procfs/
 |   |   `- README.txt
 |   `- unionfs/
 |       `- README.txt
 |- graphics/
 |   `- README.txt
 |- lib/
 |   `- README.txt
 |- libc/
 |   `- README.txt
 |- libnx/
 |   `- README.txt
 |- libxx/
 |   `- README.txt
 |- mm/
 |   |- shm/
 |   |   `- README.txt
 |   `- README.txt
 |- net/
 |   `- README.txt
 |- syscall/
 |   `- README.txt
 `- tools/
     `- README.txt

apps
 |- examples/
 |   |- bastest/README.txt
 |   |- json/README.txt
 |   |- pashello/README.txt
 |   `- README.txt
 |- graphics/
 |   `- tiff/README.txt
 |- interpreters/
 |   |- bas
 |   |  `- README.txt
 |   |- ficl
 |   |  `- README.txt
 |   `- README.txt
 |- modbus/
 |   `- README.txt
 |- netutils/
 |   |- discover
 |   |  `- README.txt
 |   |- ftpc
 |   |  `- README.txt
 |   |- json
 |   |  `- README.txt
 |   |- telnetd
 |   |  `- README.txt
 |   `- README.txt
 |- nshlib/
 |   `- README.txt
 |- NxWidgets/
 |   `- README.txt
 |- system/
 |   |- cdcacm
 |   |  `- README.txt
 |   |- i2c
 |   |  `- README.txt
 |   |- inifile
 |   |  `- README.txt
 |   |- install
 |   |  `- README.txt
 |   |- nxplayer
 |   |  `- README.txt
 |   |- usbmsc
 |   |  `- README.txt
 |   |- zmodem
 |   |  `- README.txt
 |   `- zoneinfo
 |      `- README.txt
 `- README.txt

 NxWidgets
 |- Doxygen
 |   `- README.txt
 |- tools
 |   `- README.txt
 |- UnitTests
 |   `- README.txt
 `- README.txt