Error linking in crosscompile
lazarus / 1-Linux

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BlueIcaro · 2020-10-28 10:48

Hello, I have a binding unit to a library. In my unit I have this
code:
Code: [Select]  gevlib = 'libGevApi.so';  
(...)
// Get the number of Gev devices seen by the system.
//Test OK.
function GevDeviceCount(): integer; cdecl; external gevlib;  
 I programing in Ubuntu 18.04-AMD64. I use a fpcdeluxe lazarus build,
because the final code will run in arm-linux.
When I test the code in my laptop, I have any issue. But when I change
to arm-linux compile mode I got the following error:
QuoteCompilar proyecto, Modo: jetson, CPU: arm, Objetivo: bin/linux-
arm/Testcmd: Código de salida 1, Errores: 1, Advertencias: 1
dalsa.pas(157,3) Warning: Comment level 2 found
Linking /home/jorge/Documentos/git/Lazarus-Dalsa/bin/linux-arm/Testcmd
/home/jorge/fpcupdeluxe/fpcupdeluxe/cross/bin/arm-linux/arm-linux-
gnueabihf-ld: cannot find -lGevApi
Testcmd.lpr(76,1) Error: Error while linking

I think the compiler is searching for the library. I got the library
for arm. I tried to include in compiler options/path, but I got this
error:
Quote./armlib//libGevApi.so: file not recognized: file format not
recognized

, but I don't how to include in my proyect.

Thanks for your help

/BlueIcaro

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DonAlfredo · 2020-10-28 11:07

Put the correct libGevApi.so in
/home/jorge/fpcupdeluxe/fpcupdeluxe/cross/lib/arm-linux
And with correct I mean: I guess that libGevApi.so is just a symlink.
You will need the library itself, not the symlink.

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PascalDragon · 2020-10-28 12:26

Quote from: DonAlfredo on October 28, 2020, 12:07:21 pmPut the correct
libGevApi.so in /home/jorge/fpcupdeluxe/fpcupdeluxe/cross/lib/arm-
linux
And with correct I mean: I guess that libGevApi.so is just a symlink.
You will need the library itself, not the symlink.

Symlinks are correctly handled by ld.

Quote from: BlueIcaro on October 28, 2020, 11:48:37 amI think the
compiler is searching for the library. I got the library for arm. I
tried to include in compiler options/path, but I got this error:
Quote./armlib//libGevApi.so: file not recognized: file format not
recognized

, but I don't how to include in my proyect.

You need to add the path where the library resides in with -Fl....

Would you also please provide the output of file
/path/to/libGevApi.so?

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BlueIcaro · 2020-11-03 15:32

BTW, I make a mistake in my first post, the cpu target is aarch64.

QuoteWould you also please provide the output of file
/path/to/libGevApi.so?
I don't know what is it?.
Give me some instructions to provide that info to you.

/BlueIcaro

Edit: PascalDragron do you want to say the output when I try to
compile?. I got this info from console
QuoteHint: (lazarus) Project needs building: Compile was incomplete
for Project
[TCompiler.Compile] CmdLine="/home/jorge/fpcupdeluxe/fpcupdeluxe/fpc/b
in/x86_64-linux/fpc.sh  -Tlinux -Paarch64 -MObjFPC -Scghi -CX -O3 -XX
-l -vewnhibq -Fi/home/jorge/Documentos/git/Lazarus-
Dalsa/lib/aarch64-linux -Fl/home/jorge/Documentos/git/Lazarus-
Dalsa/armlib/lib/lib -Fu/home/jorge/Documentos/git/Lazarus-Dalsa/
-FU/home/jorge/Documentos/git/Lazarus-Dalsa/lib/aarch64-linux/
-FE/home/jorge/Documentos/git/Lazarus-Dalsa/bin/linux-aarch64/
-o/home/jorge/Documentos/git/Lazarus-Dalsa/bin/linux-aarch64/Testcmd
Testcmd.lpr"
Info: (lazarus) Execute Title="Compilar proyecto, Modo: jetson, CPU:
aarch64, Objetivo: bin/linux-aarch64/Testcmd"
Info: (lazarus) Working Directory="/home/jorge/Documentos/git/Lazarus-
Dalsa/"
Info: (lazarus) Executable="/home/jorge/fpcupdeluxe/fpcupdeluxe/fpc/bi
n/x86_64-linux/fpc.sh"
Info: (lazarus) Param[0]="-Tlinux"
Info: (lazarus) Param[1]="-Paarch64"
Info: (lazarus) Param[2]="-MObjFPC"
Info: (lazarus) Param[3]="-Scghi"
Info: (lazarus) Param[4]="-CX"
Info: (lazarus) Param[5]="-O3"
Info: (lazarus) Param[6]="-XX"
Info: (lazarus) Param[7]="-l"
Info: (lazarus) Param[8]="-vewnhibq"
Info: (lazarus) Param[9]="-Fi/home/jorge/Documentos/git/Lazarus-
Dalsa/lib/aarch64-linux"
Info: (lazarus) Param[10]="-Fl/home/jorge/Documentos/git/Lazarus-
Dalsa/armlib/lib/lib"
Info: (lazarus) Param[11]="-Fu/home/jorge/Documentos/git/Lazarus-
Dalsa/"
Info: (lazarus) Param[12]="-FU/home/jorge/Documentos/git/Lazarus-
Dalsa/lib/aarch64-linux/"
Info: (lazarus) Param[13]="-FE/home/jorge/Documentos/git/Lazarus-
Dalsa/bin/linux-aarch64/"
Info: (lazarus) Param[14]="-o/home/jorge/Documentos/git/Lazarus-
Dalsa/bin/linux-aarch64/Testcmd"
Info: (lazarus) Param[15]="Testcmd.lpr"
[TCompiler.Compile] end
Hint: (lazarus) [TMainIDE.DoBuildProject] compiler time in s:
0,135000399313867
Error: (lazarus) [TMainIDE.DoBuildProject] Compile failed

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PascalDragon · 2020-11-04 08:22

No, I meant what I said:

Code: [Select]$> file /path/to/libGevApi.so
E.g. on my system for libc it will look like this:

Code: [Select]sb@Merkur:~$ file /lib/x86_64-linux-gnu/libc-2.27.so
/lib/x86_64-linux-gnu/libc-2.27.so: ELF 64-bit LSB shared object,
x86-64, version 1 (GNU/Linux), dynamically linked, interpreter
/lib64/ld-linux-x86-64.so.2,
BuildID[sha1]=d3cf764b2f97ac3efe366ddd07ad902fb6928fd7, for GNU/Linux
3.2.0, stripped
Nevertheless regarding the output you provided: is the path to your
libGevApi.so part of the paths listed there with -Fl?

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BlueIcaro · 2020-11-04 17:34

Hi, file comand returns this:
Quotefile /usr/local/lib/libGevApi.so
/usr/local/lib/libGevApi.so: symbolic link to
/usr/local/lib/libGevApi.so.2
After put libGevApi.so in the path -Fl, I make a small step. Because I
got a lot of warnings, and after a new linking error:
Quote/home/jorge/fpcupdeluxe/fpcupdeluxe/cross/bin/arm-linux/arm-
linux-gnueabihf-ld: warning: libCorW32.so.1, needed by
./LibPi//libGevApi.so, not found (try using -rpath or -rpath-link)
/home/jorge/fpcupdeluxe/fpcupdeluxe/cross/bin/arm-linux/arm-linux-
gnueabihf-ld: warning: libGenApi_gcc46_v3_0.so, needed by
./LibPi//libGevApi.so, not found (try using -rpath or -rpath-link)
/home/jorge/fpcupdeluxe/fpcupdeluxe/cross/bin/arm-linux/arm-linux-
gnueabihf-ld: warning: libGCBase_gcc46_v3_0.so, needed by
./LibPi//libGevApi.so, not found (try using -rpath or -rpath-link)

So I add all library that I found in the compiler messages.
But I couldn't solve the last one. This:
Quote/home/jorge/fpcupdeluxe/fpcupdeluxe/cross/bin/arm-linux/arm-
linux-gnueabihf-ld: ./LibPi//libGevApi.so: undefined reference to
`fcntl@GLIBC_2.28'
/BlueIcaro

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DonAlfredo · 2020-11-04 18:32

You are doing good ! 
However. You have now encountered a more difficult problem. Let me
explain.

You are cross-compiling towards linux-arm. This OS has its own libs
with its own versions of glibc and other libraries.

To allow you to cross-compile, fpcupdeluxe has downloaded its own,
more or less general Linux arm libs. I just had a look at the GNU C
Library: Ubuntu GLIBC 2.24. Older than the libs you need to link
against your own version of libGevApi.

So, you have a version mismatch.
Replace all cross arm-linux libs from fpcupdeluxe with libs from your
own system. You will be certain that your app will work on your
system. With the right versions.
Brute force:
Delete all fpcupdeluxe libs.
Copy all the libs from your arm-system /lib and usr/lib. Thats a lot,
but will work.