sdsoc opencv configuration

[1ymw1]

hi,

I have my own rootfs generated from petalinux, and it includes the opencv, I am trying to develop my vision algorithm based on this opencv in sdsoc, BUT I am getting error about linking opencv with sdsoc. If I use CHaiDNN opencv from here, everything works without any problem. and I have tried to use existing opencv in sdk but I face to the same problem.please help

[hokim]

Hi

Does your sysroot(rootfs) have libopencv_core.so ?

The error message says gcc compiler can't find libopencv_*.so 

[1ymw1]

hi @hokim,

I generated petalinux rootfs in ubuntu machine and sdsoc is installed in windows machine, as far as I know, if I give the complete link for  /usr/lib and /usr/include it is not a problem, right?. if it is not enough can you tell me how to include opencv link to SYSROOT in windows machine, ?

thank you very much for reply.

[hokim]

Hi

I mean you should check filelist in your sysroot directory like this

$ find sysroot -name 'libopencv_core.so*'
sysroot/usr/lib/libopencv_core.so
sysroot/usr/lib/libopencv_core.so.3.3
sysroot/usr/lib/libopencv_core.so.3.3.0

Can you see libopencv_core.so ?

If you can't see it , you should check whether your petalinux image recipe includes packagegroup-petalinux-opencv-dev

Image recipe needs *-dev for *.so files

[1ymw1]

Dear @hokim,

yes, I have double checked everytime whether evey *.so files are in the petalinux rootfs  /usr/bin and also *.hpp files in /usr/include .

thanks

[hokim]

I mean libopencv_core.so not libopencv_core.so.3*

Even though libopencv_core.so is actually symbolic link to libopencv_core.so.3.3,

gcc compiler require libopencv_core.so not libopencv_core.so.3* for build

If your rootfs has *.so file, I don't understand why such error message happended 

At last, could you build your project on linux system?

Windows system might not treat linux symbolic link properly 

[1ymw1]

hi @hokim

you are correct, this problem is regarding the *.so files, in the windows *.so files do not linked with *.so.3.3 and *.so.3.3.0 properly. you can see in the images the *.so files and *.so.3.3 files have very less size when they are in windows computer, but these files show big size when they are in linux computer, I think they are not properly linked with each other, so what I did is I convert all the *.so.3.3.0 files into *.so.3.3 and *.so files by renaming *.so.3.3.0 files, in this way I was able to builld my project in sdsoc without any problem, do you think it is a good practise? I get these files from unpacking rootfs.tar.gz in linux computer into pen driver and use these files in sdsoc in windows machine.

[1ymw1]

hi @hokim

you are correct, this problem is regarding the *.so files, in the windows *.so files do not linked with *.so.3.3 and *.so.3.3.0 properly. you can see in the images the *.so files and *.so.3.3 files have very less size when they are in windows computer, but these files show big size when they are in linux computer, I think they are not properly linked with each other, so what I did is I convert all the *.so.3.3.0 files into *.so.3.3 and *.so files by renaming *.so.3.3.0 files, in this way I was able to builld my project in sdsoc without any problem, do you think it is a good practise? I get these files from unpacking rootfs.tar.gz in linux computer into pen driver and use these files in sdsoc in windows machine.

[hokim]

This is how to solve linux symbolic link on  Windows

$ mkdir tmp
$ cd tmp
$ tar xvzf ../rootfs.tar.gz
$ zip -r ../rootfs.zip .

linux zip command replace  symbolic link with linked file 

Use rootfs.zip in Windows

[nutang]

Hi @1ymw1

Are you still facing this issue?

[1ymw1]

Dear @hokim , @nutang,

I am sorry about the late responce, using zip format in windows solved the problem in great degree. but there are few poor *.so files which could not to find the linked files because they were in another directory, for example, in my case,  in the libpthread.so, have statements as follow,

/* GNU ld script
Use the shared library, but some functions are only in
the static library, so try that secondarily. */
OUTPUT_FORMAT(elf32-littlearm)
GROUP ( /lib/libpthread.so.0 /usr/lib/libpthread_nonshared.a )

as you can notice here the linked files of libpthread.so are in the rootfs/lib and rootfs/usr/lib but libpthread_nonshared.a was already in the rootfs/usr/lib, so what I did is copied the libpthread.so file from rootfs/lib to rootfs/usr/lib and change the statement "GROUP ( /lib/libpthread.so.0 /usr/lib/libpthread_nonshared.a )" to this "GROUP ( libpthread.so.0 libpthread_nonshared.a )"

And I did the same thing to the libc.so as follow

"GROUP (/lib/libc.so.6    /usr/libc_nonshared.a  AS_NEEDED ( /lib/ld-linux-armhf.so.3) )" to

"GROUP (libc.so.6    libc_nonshared.a  AS_NEEDED ( ld-linux-armhf.so.3) )"

and I copied te libc.so.6 and ld-linux-armhf.so.3 from /rootfs/lib to rootfs/usr/lib

in this way I was able to compile my code sucessfully. But I need to know that is this the correct way to do this? will this cause to future problem??? I am going to develop my whole algorithm on sdsoc,so I need to verify that I have done everything in correct way.

and Dear @hokim you have been very kind to me. you have tried to give me a solution for many cases, thank you. thank you so much.

[nutang · Accepted solution]

Hi @1ymw1

Please try below option,

Navigate to C/C++ build settings->C/C++ Build-> Settings->SDS++ Linker->Miscellaneous->Linker Flags

Add below line, (If there are other flags already present, please retain)

--sysroot=${SYSROOT} -L=/lib -L=/usr/lib -Wl,-rpath-link=${SYSROOT}/lib,-rpath-link=${SYSROOT}/usr/lib

[1ymw1]

hi @nutang

I re-extract my rootfs.zip and tried your script for linker flag, but it didnt work, I am using sdsoc(2018.2) in windows computer and I generated rootfs.zip in linux computer, compiler says,

cannot find /lib/libpthread.so.0

cannot find usr//lib/libppthread_nonshared.a

please read this thread from beggining. thanks

[nutang]

hi @1ymw1

This is the correct way to link the pthread library in run time, I have tested it multiple times.

If you have set $SYSROOT properly, 

clean and build again. 

[1ymw1]

hi @nutang

can you please tell me how to set $SYSROOT in sdsoc in windows machine? ussually I give the complete path to the rootfs folder. example:

c:/rootfs/lib

c:rootfs/usr/lib

thanks

[nutang]

Hi @1ymw1

• Windows: Go to Start → Control Panel → System → Advanced → Environment Variables. Create an environment variable SYSROOT with the value <platform>/sw/a53_linux/a53_linux/sysroot/aarch64-xilinx-linux/.

[nutang]

Hi @1ymw1

Which platform you are using?

[1ymw1]

hi @nutang

wow, it works...... needed to restart the software. no need to change the content in any of the *.so files. thank you so much.

[nutang]

Hi @1ymw1

I am glad that it helped you.

[1ymw1]

hi @nutang

I am using zedboard, with my own rootfs generated in petalinux with opencv. I added variable name with SYSROOT and c:\rootfs

thanks again for the concern