Adding Qt stack to embedded linux kerenel
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for testing purposes, is it possible to install the qt-everywhere-opensource-src-4.8.6 on the host computer, and then run the qt demos on my embedded Linux (target board) via NFS to retrieve the bin files from my host computer?
I tried this method but I get the following error:
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Yes, usually, the SDK provides the cross-compiler or if not, a mean to get one. What you will also need is the "dev" version of the packages you installed on your rootfs in order to get the dependencies needed for Qt and your application (e.g. OpenSSL)
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I managed to compiled executable files for my embedded Linux board using arms arch. using my SDK compiler (using the Qt-everywhere-opensource-4.8.6).
FYI, because i'm just want to run a quick test for the Qt demos, i'm actually accessing the following files below (i.e. framebuffer; deform; books) on my Putty terminal, via my NSF that is linked to the host computer running on Ubuntu.
In addition, my lib folder in my embedded development board does nt contain the Qt lib files, but those Qt lib files are instead residing in my NSF folder. Do I also need to append my .profile file in my embedded Linux to point to the NSF path for the required lib files?
Will these pose problems as described in the following 3 errors when i'm executing the demos / examples in my putty terminal (i.e. running on embedded development board)?
Error 1:
When I tried to execute a Qt demo in my Putty terminal, it says:
/mnt/QtEmbedded-4.8.6-arm/examples/qws/framebuffer # ./framebuffer
Error: cannot open framebuffer device: Operation not permittedError 2:
when I tried to execute deform demo on putty terminal, it says:
/mnt/QtEmbedded-4.8.6-arm/demos/deform # ./deform Bus errorError 3:
when I tried to execute books demo on putty terminal, it says:
./books: error while loading shared libraries: libQtSql.so.4: cannot open shared object file: No such file or directory -
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You're a standard user and the
/dev/fb0access rights don't include you -
I don't remember exactly but IIRC, there was a device involved e.g. error accessing the frame buffer but not related to rights.
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It usually means that you don't have the Qt libraries installed on your target.
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Hi SGaist,
thanks for the note; which means I won't be able to run the Qt demos (that are residing on my HOST Ubuntu PC) on my target embedded board without the Qt lib?. I tried to point the path to the NFS in .profile file i.e.
PATH=/mnt/QtEmbedded-4.8.6-arm/bin
PATH=/mnt/QtEmbedded-4.8.6-arm/libbut apparently this didn't help as I still can't run the demos.
For Point #1, is there a way to include access in fb0? apparently my kernel image doesn't support sudo function though, Does it mean I need to get a new kernel image with sudo function?
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If you don't have sudo you may have su alone.
Well, you're building an application with Qt, so unless you make everything static, then yes, you need Qt on your target.
Where are you setting
PATH? -
I see. That probably explains why I can run the demos / examples on the host PC with the environment setup as my target board doesn't include Qt libraries. I'm setting my PATH in /etc/profile/ :
/etc/profile: system-wide .profile file for the Bourne shells
set_path_before()
{
[ -d $1 ] && PATH="$1:$PATH"
}PATH="/usr/bin:/usr/sbin:/bin:/sbin"
set_path_before /usr/local/sbin
set_path_before /usr/local/bin*************************************************
PATH to Qt lib & bin on HOST PC
------------------------------
PATH=/mnt/QtEmbedded-4.8.6-arm/bin:$PATH
PATH=/mnt/QtEmbedded-4.8.6-arm/lib:$PATH************************************************
LD_LIBRARY_PATH="/usr/local/lib:/usr/lib"
export PATH
How about if I copy the entire Qt lib from HOST to TARGET, and then point the path to my TARGET/lib files, would that work if I run the Qt demo on the HOST (via NFS), the Qt lib now sitting on my TARGET board?
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btw, I tried to make directory Qtlib and then copy the entire Qt lib from my HOST PC into my TARGET BOARD (/Qtlib):
mkdir /lib/Qtlib
cp -r /mnt/QtEmbedded-4.8.6-arm/lib /lib/QtlibHowever, when I tried to change my PATH on my TARGET BOARD, i'm unable to save the file in vi editor.
(i.e. /etc/profile)At this juncture, I tried to create a mkdir 'test' on root to test out i.e. mkdir /home/test and was returned with the following error:
/ # mkdir /home/aa
mkdir: can't create directory '/home/aa': Cannot allocate memoryI tried to reboot embedded Linux but still unable to edit and save changes in my profile using vi editor.
My memory at that juncture is
Total = 119MB
Used = 35 MB
Free = 83 MB -
For /etc/profile you need root access. So first call su and then start vi.
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Linux is not Windows, PATH is only used to find executable not libraries.
You can use
LD_LIBRARY_PATHfor that. -
@jsulm it seems that my su command is not functional; when I use the command, it'll just go from my root to /~. Nonetheless, when I execute vi, I don't need root access when I type [vi profile]
@SGaist Tkx, I've amended and appended LD_LIBRARY_PATH="/mnt/QtEmbedded-4.8.6-arm/lib" to my profile file in /etc/profile but i'm still having the same problem when running framebuffer - unable to find libQtGui.so.4.
Could it be during cross-compilation, I could have missed out any variables when performing [Make] command?
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Were did you modify these variables ?
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btw, i'm looking at qt-everywhere-enterprise-5.7 sources and what does it mean by 'sysroot'? Where may I locate my sysroot path?
http://doc.qt.io/qt-5/embedded-linux.html@embdev sysroot is the file-system (or part of it) of your target device. You can mount it wherever you want (or just copy it to a location). You need the sysroot to be able to cross-compile for your target as it contains all the libs and header files.
