somehow

Developing Applications on a Raspberry Pi with QEMU on Windows 10

This is a tutorial showing how to develop Qt applications for the Raspberry Pi 3 cross compiling on Windows, using MYSYS2 with GCC and arm tool chain.

Installation

Download the latest version of Windows toolchain for Raspberry/PI e.g raspberry-gcc6.3.0-r3 and install it.
Download and install MSYS2. I used the msys2-x86_64-20180531.exe version, after the successful installation, run MSYS2 and execute the following commands:
```
pacman -Syu
pacman -S base-devel git mercurial cvs wget p7zip
pacman -S perl ruby python2 mingw-w64-i686-toolchain mingw-w64-x86_64-toolchain
```
Set the paths for mingw32 and mingw64. I modified .bash_profile file located under C:\msys64\home\napiZip. I added the following section in order to make the tool chain for the Raspberry available by adding the Windows toolchain for Raspberry/PI folder containing the arm-linux-gnueabihf-... .exe files:

PATH="${PATH}:/C/SysGCC/raspberry/bin"

Note:
After setting the path you should be able to run the following commands otherwise your path was not set correctly:

 $ arm-linux-gnueabihf-gcc -v

Using built-in specs.
COLLECT_GCC=C:\SysGCC\raspberry\bin\arm-linux-gnueabihf-gcc.exe
COLLECT_LTO_WRAPPER=c:/sysgcc/raspberry/bin/../libexec/gcc/arm-linux-gnueabihf/6/lto-wrapper.exe
Target: arm-linux-gnueabihf
Configured with: ../../gcc-6-6.3.0/src/configure -v --with-pkgversion='Raspbian 6.3.0-18+rpi1' --with-bugurl=file:///usr/share/doc/gcc-6/README.Bugs --enable-languages=c,c++ --enable-shared --enable-linker-build-id --without-included-gettext --enable-threads=posix --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-libitm --disable-libquadmath --with-system-zlib --disable-browser-plugin --enable-gtk-cairo --with-arch-directory=arm --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-sjlj-exceptions --with-arch=armv6 --with-fpu=vfp --with-float=hard --enable-checking=release --target=arm-linux-gnueabihf --host=i686-w64-mingw32 --prefix /q/gnu/raspberry/out/ --with-sysroot=/q/gnu/raspberry/out/arm-linux-gnueabihf/sysroot
Thread model: posix
gcc version 6.3.0 20170516 (Raspbian 6.3.0-18+rpi1)

$  g++ -v
Using built-in specs.
COLLECT_GCC=C:\msys64\mingw32\bin\g++.exe
COLLECT_LTO_WRAPPER=C:/msys64/mingw32/bin/../lib/gcc/i686-w64-mingw32/7.3.0/lto-wrapper.exe
Target: i686-w64-mingw32
Configured with: ../gcc-7.3.0/configure --prefix=/mingw32 --with-local-prefix=/mingw32/local --build=i686-w64-mingw32 --host=i686-w64-mingw32 --target=i686-w64-mingw32 --with-native-system-header-dir=/mingw32/i686-w64-mingw32/include --libexecdir=/mingw32/lib --enable-bootstrap --with-arch=i686 --with-tune=generic --enable-languages=c,lto,c++,objc,obj-c++,fortran,ada --enable-shared --enable-static --enable-libatomic --enable-threads=posix --enable-graphite --enable-fully-dynamic-string --enable-libstdcxx-time=yes --enable-libstdcxx-filesystem-ts=yes --disable-libstdcxx-pch --disable-libstdcxx-debug --disable-isl-version-check --enable-lto --enable-libgomp --disable-multilib --enable-checking=release --disable-rpath --disable-win32-registry --disable-nls --disable-werror --disable-symvers --with-libiconv --with-system-zlib --with-gmp=/mingw32 --with-mpfr=/mingw32 --with-mpc=/mingw32 --with-isl=/mingw32 --with-pkgversion='Rev2, Built by MSYS2 project' --with-bugurl=https://sourceforge.net/projects/msys2 --with-gnu-as --with-gnu-ld --disable-sjlj-exceptions --with-dwarf2
Thread model: posix
gcc version 7.3.0 (Rev2, Built by MSYS2 project)

Install and set up QEMU with a Raspberry image distribution, for details see my repository here.

Build Tutorial

This tutorial shows the exact steps needed to generate the build artifacts for the Raspberry Pi 3, as well as how to run applications created with Qt within QEMU.

Download the latest version of the Qt source code. I used qt-everywhere-src-5.11.2.
Extract the file qt-everywhere-src-5.11.2.zip into any directory of desire.
In order to build for the Raspberry Pi we need to make sure that our sysroot directory is up to date. We need to ensure that we are linking against the same libraries and we have the same headers as base. The Windows toolchain for Raspberry Pi offers a handy batch script which supports us, the script is called UpdateSysroot.bat and is located in SysGCC\raspberry\TOOLS. I used the following settings to connect to QEMU:

Host name: 127.0.0.1
User name: pi

I downloaded the sysroot into the following directory C:\SysGCC\raspberry\arm-linux-gnueabihf\sysroot.
Note:
SmartTTY is only able to connect to port 22, if you changed the port routing in QEMU, make sure that 22 is available in order to connect, or use netsh to create a port proxy, an example can be found here. 4. The next step after the successful download of the sysroot directory is to configure the build. I used mingw32.exe , and changed the directory to /c/SysGCC/raspberry in my case. The following section shows the creation of a qt-build directory, which is then used for the build artifacts, and then the command in order to configure the Qt build.

mkdir qt-build
cd qt-build

../qt-everywhere-src-5.11.2/configure -platform win32-g++ -device linux-rasp-pi3-g++ -release -sysroot C:/SysGCC/raspberry/arm-linux-gnueabihf/sysroot -prefix /usr/local/qt5 -device-option "CROSS_COMPILE=arm-linux-gnueabihf-" -nomake examples -opensource -confirm-license

After the configuration is done successfully we need to execute the build, within the qt-build directory, with the following command:

mingw32-make

Copy the build artefacts by running:

mingw32-make install

Note:
The files are copied into the sysroot directory, the exact location depends on how the Qt build was configured, the prefix specifies the location within the sysroot directory, in this case C:\SysGCC\raspberry\arm-linux-gnueabihf\sysroot\usr\local\qt5. You should see more sub folder within this directory e.g. bin, include and lib. 7. Open SmarTTY.exe, select the target as defined in step tree and connect. Then run the following command:

cd /usr/local
sudo mkdir qt5
sudo chown pi qt5

Upload the build artefacts with SmarTTY.exe. Select SCP-> Upload. I used the following path: C:\SysGCC\raspberry\arm-linux-gnueabihf\sysroot\usr\local\qt5
Run a test application e.g. qtdiag which is located in the bin directory by calling:

./qtdiag

Problems

Here are some issues I ran into. I am hoping by showing some problems and their solutions you guys can adapt the approaches to your problems.

Here is an error which occurred during building after I created the configuration.

'C:\SysGCC\raspberry\qt-build\qtbase\bin\moc.exe' -DQT_NO_URL_CAST_FROM_STRING -DQT_NO_INTEGER_EVENT_COORDINATES -DQT_NO_FOREACH -DWTF_EXPORT_PRIVATE= -DJS_EXPORT_PRIVATE= -DENABLE_ASSEMBLER_WX_EXCLUSIVE=1 -DWTFReportAssertionFailure=qmlWTFReportAssertionFailure -DWTFReportAssertionFailureWithMessage=qmlWTFReportAssertionFailureWithMessage -DWTFReportBacktrace=qmlWTFReportBacktrace -DWTFInvokeCrashHook=qmlWTFInvokeCrashHook -DENABLE_LLINT=0 -DENABLE_DFG_JIT=0 -DENABLE_DFG_JIT_UTILITY_METHODS=1 -DENABLE_JIT_CONSTANT_BLINDING=0 -DBUILDING_QT__ -DWTF_USE_UDIS86=0 -DNDEBUG -DQT_NO_NARROWING_CONVERSIONS_IN_CONNECT -DQT_BUILD_QML_LIB -DQT_BUILDING_QT -DQT_NO_CAST_TO_ASCII -DQT_ASCII_CAST_WARNINGS -DQT_MOC_COMPAT -DQT_USE_QSTRINGBUILDER -DQT_DEPRECATED_WARNINGS -DQT_DISABLE_DEPRECATED_BEFORE=0x050000 -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_NO_DEBUG -DQT_NETWORK_LIB -DQT_CORE_LIB -D__ARM_ARCH_6__ --include C:/SysGCC/raspberry/qt-build/qtdeclarative/src/qml/.moc/moc_predefs.h -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtbase/mkspecs/devices/linux-rasp-pi3-g++ -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/memory -IC:/SysGCC/raspberry/qt-build/qtdeclarative/src/qml -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/compiler -IC:/SysGCC/raspberry/qt-build/qtdeclarative/src/qml -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/jsruntime -IC:/SysGCC/raspberry/qt-build/qtdeclarative/src/qml -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/jit -IC:/SysGCC/raspberry/qt-build/qtdeclarative/src/qml -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/debugger -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/animations -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/jit -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/assembler -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/runtime -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/wtf -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/stubs -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/stubs/wtf -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/disassembler -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/3rdparty/masm/disassembler/udis86 -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/.generated -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/include -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/include/QtQml -IC:/SysGCC/raspberry/qt-build/qtdeclarative/include -IC:/SysGCC/raspberry/qt-build/qtdeclarative/include/QtQml -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/include/QtQml/5.11.2 -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/include/QtQml/5.11.2/QtQml -IC:/SysGCC/raspberry/qt-build/qtdeclarative/include/QtQml/5.11.2 -IC:/SysGCC/raspberry/qt-build/qtdeclarative/include/QtQml/5.11.2/QtQml -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtbase/include/QtCore/5.11.2 -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtbase/include/QtCore/5.11.2/QtCore -IC:/SysGCC/raspberry/qt-build/qtbase/include/QtCore/5.11.2 -IC:/SysGCC/raspberry/qt-build/qtbase/include/QtCore/5.11.2/QtCore -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtbase/include -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtbase/include/QtNetwork -IC:/SysGCC/raspberry/qt-build/qtbase/include -IC:/SysGCC/raspberry/qt-build/qtbase/include/QtNetwork -IC:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtbase/include/QtCore -IC:/SysGCC/raspberry/qt-build/qtbase/include/QtCore -I. -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/include/c++/6 -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/include/c++/6/backward -Ic:/sysgcc/raspberry/lib/gcc/arm-linux-gnueabihf/6/include -Ic:/sysgcc/raspberry/lib/gcc/arm-linux-gnueabihf/6/include-fixed -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/include -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/include/arm-linux-gnueabihf/c++/6 -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include/arm-linux-gnueabihf -Ic:/sysgcc/raspberry/arm-linux-gnueabihf/sysroot/usr/include C:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtdeclarative/src/qml/util/qqmladaptormodel.cpp -o .moc/qqmladaptormodel.moc
mingw32-make[2]: *** [Makefile:12064: .moc/qqmladaptormodel.moc] Error -1073741701
mingw32-make[2]: Leaving directory 'C:/SysGCC/raspberry/qt-build/qtdeclarative/src/qml'
mingw32-make[1]: *** [Makefile:53: sub-qml-make_first-ordered] Error 2
mingw32-make[1]: Leaving directory 'C:/SysGCC/raspberry/qt-build/qtdeclarative/src'
mingw32-make: *** [Makefile:48: sub-src-make_first] Error 2

I used err.exe to resolve the error code.

C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin>err.exe -1073741701
# for decimal -1073741701 / hex 0xc000007b
  STATUS_INVALID_IMAGE_FORMAT                                    ntstatus.h
# {Bad Image}
# %hs is either not designed to run on Windows or it contains
# an error. Try installing the program again using the
# original installation media or contact your system
# administrator or the software vendor for support.
# as an HRESULT: Severity: FAILURE (1), FACILITY_NULL (0x0), Code 0x7b
# for decimal 123 / hex 0x7b
  ERROR_INVALID_NAME                                             winerror.h
# The filename, directory name, or volume label syntax is
# incorrect.
# 2 matches found for "-1073741701"

Turns out that the error code -1073741701 = 0x000007b is translated to ERROR_INVALID_NAME. The reason for this particular error was using double forward slashes //, notice also the inconsistent use of them for the -prefix argument -prefix //usr//local/qt5:

../qt-everywhere-src-5.11.2/configure.bat -platform win32-g++ -device linux-rasp-pi3-g++ -release -sysroot C://SysGCC//raspberry//arm-linux-gnueabihf//sysroot -prefix //usr//local/qt5 -device-option "CROSS_COMPILE=arm-linux-gnueabihf-" -nomake examples -opensource -confirm-license

Here is a different error I encountered so far:

pi@raspberrypi:/usr/local/qt5/bin $ ./qtdiag
Illegal instruction

This is the output I get when I execute the application in gdb:

and "show warranty" for details.
This GDB was configured as "arm-linux-gnueabihf".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from qtdiag...(no debugging symbols found)...done.
(gdb) r
Starting program: /usr/local/qt5/bin/qtdiag
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/arm-linux-gnueabihf/libthread_db.so.1".

Program received signal SIGILL, Illegal instruction.
0xb610cb30 in qRegisterResourceData(int, unsigned char const*, unsigned char const*, unsign
ed char const*) () from /usr/local/qt5/lib/libQt5Core.so.5

One major problem I encountered is that for some reason the install path is somehow not correct. Take a look at the qt.conf, the DevicePaths, Prefix and HostPrefix are not correct, since they are not absolute and the HostPath contains the local drive.

[EffectivePaths]
Prefix=..
[DevicePaths]
Prefix=C:/usr/local/qt5
[Paths]
Prefix=C:/usr/local/qt5
HostPrefix=C:/SysGCC/raspberry/arm-linux-gnueabihf/sysrootC:/usr/local/qt5
Sysroot=C:/SysGCC/raspberry/arm-linux-gnueabihf/sysroot
SysrootifyPrefix=true
TargetSpec=devices/linux-rasp-pi-g++
HostSpec=win32-g++
[EffectiveSourcePaths]
Prefix=C:/SysGCC/raspberry/qt-everywhere-src-5.11.2/qtbase

This leads to the fact, that some environment variables need to be set in order to run Qt applications, I used the folowing commands to resolve that issue:

#!/bin/bash

export LD_LIBRARY_PATH=/usr/local/qt5/lib
export QT_QPA_PLATFORM_PLUGIN_PATH=/usr/local/qt5/plugins/platforms
export QT_QPA_FONTDIR=/user/share/fonts
sudo ldconfig

Special thanks to

I thank etiennedm, for an awesome article which I used as a starting point. Also thanks to the people from visualgdb.com.

Contributing, Help, Feedback and Questions