Cross Compile from Windows to Linux ARM
lazarus / 32-Linux

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LA.Center · 2012-03-19 00:24

Hi I am trying to cross compile on Windows 32 to Linux ARM and I get
this message:

arm-linux-ld.exe: cannot find -lpthread

Does anyone know where I can find this lib?

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Andru · 2012-03-19 01:10

When you compile something from Windows to Linux ARM you should
already have some standard libs(libc.so, libdl.so, etc.), and
libpthread one of them, so this is a bit strange. You need to get
GNU/Linux(with support of ARM) distributive where you want to execute
your application and extract from there libpthread.so.

PS: this situation is very familiar to compilation for Android.
Unfortunately FreePascal doesn't support threads for Android at all
because of different version of pthreads on Android(there are limited
functions of it implemented there, and all functions placed in libc.so
instead of libpthread.so). And if you want to use threads on Android
you need to use pthreads directly.

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LA.Center · 2012-03-19 07:16

I am actually pointing to android-ndk-r7\platforms\android-8\arch-
arm\usr\lib which sould contain all the libs afak.

still getting the same link error.

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Andru · 2012-03-19 08:18

Quotewhich sould contain all the libs afak.As I wrote previously in PS
- you won't find this library for Android, because there is no
libpthread. You need to comment cthreads in uses clause of your
project and don't use standard thread functions like BeginThread and
so on.

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LA.Center · 2012-03-19 08:44

thx for the info, but I am only using System and Classes unit to
create a library.so I don't use any threads and I don't have cthread
in my uses clause.

my config is FPC 2.7 cross compiled for linux-arm.

Is there maybe something I need to specify in project options?

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Andru · 2012-03-19 08:57

QuoteIs there maybe something I need to specify in project
options?There is no option for this. Something is definitely using
cthreads in your project(because only that unit has {$linklib
pthreads} line), or something changed in FreePascal 2.7.x. E.g. I use
FreePascal 2.6.x from fix_2_6 branch and there is no problem with
pthread till I'm not using cthreads.

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LA.Center · 2012-03-19 09:07

thx a lot for your help, I am giving up and go back to linux for
linux-arm development. It would have been cool though to get it
working in windows too.


BTW: I tried even this:

library test;
begin
end.

and it still got the link error, so I am guessing 2.7 branch is not
suited for arm-linux

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Andru · 2012-03-19 09:19

Strange... I will try to build FPC 2.7 here and test it.

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Andru · 2012-03-19 09:39

Works for me. I built FreePascal 2.7 and have no problems with
pthread(the only problem was path to libdl.so, which is not needed for
FreePascal 2.6.x). Custom options of my project contains next:
Code: [Select]-Cparmv5
-CfSOFT
-XParm-linux-androideabi-
-Xd
-FD${LazarusDir}..\android-ndk-r7\toolchains\arm-linux-
androideabi-4.4.3\prebuilt\windows\bin
-Fu${LazarusDir}..\android-ndk-r7\platforms\android-3\arch-arm\usr\lib
-FL${LazarusDir}..\android-ndk-r7\platforms\android-3\arch-
arm\usr\lib\libdl.so