[Buildroot] glibc instead of ulibc ?

[Buildroot] glibc instead of ulibc ?

[Zoran Djordjevic]

Hello
?
I've built root file system for ARM board and now try to cross
compile simple (graphical) program, using Lazarus.
Althouth I'm pretty sure that I correctly configured Lazarus, some
errors emerged?(eg. libX11.so: undefined reference to strcpy, ... fclose; fseek ...).
Seems to me?that at least part of?the?problem lies in?having uclibc,
instead of glibc. 
So my question is - how (if possible) can I?build root file system 
with glibc instead of?uclibc.
?
Best regards?
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[Buildroot] glibc instead of ulibc ?

[Thomas Petazzoni]

Le Wed, 1 Aug 2012 14:01:10 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> I've built root file system for ARM board and now try to cross
> compile simple (graphical) program, using Lazarus.
> Althouth I'm pretty sure that I correctly configured Lazarus, some
> errors emerged?(eg. libX11.so: undefined reference to strcpy, ... fclose; fseek ...).

These functions are very basic stuff in uClibc, so your problem is
most likely not uClibc here.

> Seems to me?that at least part of?the?problem lies in?having uclibc,
> instead of glibc. 
> So my question is - how (if possible) can I?build root file system 
> with glibc instead of?uclibc.

You have two choices:

 * Use the external toolchain backend, which allows you to use a
   pre-built CodeSourcery or Linaro toolchain for ARM, or build your
   own toolchain with Crosstool-NG, and then use it into Buildroot as
   an external toolchain.

 * Use the Crosstool-NG backend, which will tell Buildroot to use
   Crosstool-NG to build the toolchain.

Both of those solutions will allow you to use the glibc C library.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] glibc instead of ulibc ?

[Thomas Petazzoni]

Hello,

Please keep the Buildroot list in Cc.

Le Thu, 2 Aug 2012 06:23:26 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> I am not much familiar with process of linking, but I suppose,
> somwhere (in Lazarus units) is explicitly named glibc.so as file
> which contains necessary binaries (let's say for fclose function). It
> is so in Windows, where I must note (Delphi) dll name and function
> name or index?inside that dll,?in order for linker to find wanted
> function.) Otherwise, I don't know why linker would try to find
> eg.?fclose function exactely?in uclibc.so. Or am I wrong with that
> way of thinking ? 

Yes. The compiler knows which C library it has been linked against, and
automatically links programs against it, unless you explicitly tell it
to do otherwise.

However, I don't know what Lazarus is, and how it works, so maybe it
does funky things. If you want help, please share the current state of
the packages you're trying to add to Buildroot and let us know how to
reproduce the problem, and maybe someone will try to help on this.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] glibc instead of ulibc ?

[Zoran Djordjevic]

Excuse me, Thomas, but I don't know exactly the meaning of? "keeping
the Buildroot list in Cc", however hope this way is OK.
Shortly as possible - I build Tiny X?with Buildroot for ARM and it works
on target, including your?gtk-demo.Now I try building my own simple GUI - gtk program
?(Lazarus iz Delphi like IDE - it works OK?for me?in Linux-?i386 and could be??
adjusted?for cross compilation including ARM). I use it at Ubuntu 11.04.
For cross compiling, I use?target libraries (X11, pango, ...), built as described.
However, I probably make some mistake in first pass, and in second attempt
(few hours ago) the only error reported, AT THE MOMENT, is (like first time):? 
undefined refernece?to __libc_start_main.? 
Here http://lists.uclibc.org/pipermail/uclibc/2006-June/015659.html?I found some
statement that uClibc does not have that function (but glibc yes). 
I am aware that this question is maybe more related to other forums, but part of
it MAYBE to uClibc. So don't bother too much with this problem, just hoped that?
it?was already?recorded matter.?
?
Thanks a lot


________________________________
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Zoran Djordjevic <djdjdjole@yahoo.com> 
Cc: buildroot at uclibc.org 
Sent: Thursday, August 2, 2012 3:26 PM
Subject: Re: [Buildroot] glibc instead of ulibc ?

Hello,

Please keep the Buildroot list in Cc.

Le Thu, 2 Aug 2012 06:23:26 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> I am not much familiar with process of linking, but I suppose,
> somwhere (in Lazarus units) is explicitly named glibc.so as file
> which contains necessary binaries (let's say for fclose function). It
> is so in Windows, where I must note (Delphi) dll name and function
> name or index?inside that dll,?in order for linker to find wanted
> function.) Otherwise, I don't know why linker would try to find
> eg.?fclose function exactely?in uclibc.so. Or am I wrong with that
> way of thinking ? 

Yes. The compiler knows which C library it has been linked against, and
automatically links programs against it, unless you explicitly tell it
to do otherwise.

However, I don't know what Lazarus is, and how it works, so maybe it
does funky things. If you want help, please share the current state of
the packages you're trying to add to Buildroot and let us know how to
reproduce the problem, and maybe someone will try to help on this.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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[Buildroot] glibc instead of ulibc ?

[Thomas Petazzoni]

Hello,

Le Thu, 2 Aug 2012 12:38:35 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> Excuse me, Thomas, but I don't know exactly the meaning of? "keeping
> the Buildroot list in Cc", however hope this way is OK.

It is correct. You kept the list in copy of our discussion, which is
good.

> Shortly as possible - I build Tiny X?with Buildroot for ARM and it
> works on target, including your?gtk-demo.Now I try building my own
> simple GUI - gtk program (Lazarus iz Delphi like IDE - it works
> OK?for me?in Linux-?i386 and could be adjusted?for cross compilation
> including ARM). I use it at Ubuntu 11.04. For cross compiling, I
> use?target libraries (X11, pango, ...), built as described. However,
> I probably make some mistake in first pass, and in second attempt
> (few hours ago) the only error reported, AT THE MOMENT, is (like
> first time): undefined refernece?to __libc_start_main. Here
> http://lists.uclibc.org/pipermail/uclibc/2006-June/015659.html?I
> found some statement that uClibc does not have that function (but
> glibc yes). I am aware that this question is maybe more related to
> other forums, but part of it MAYBE to uClibc. So don't bother too
> much with this problem, just hoped that it?was already?recorded
> matter.

If you don't provide all the details needed to reproduce your problem,
there's no way we can help you. So, please provide:

 *) Your Buildroot configuration and version
 *) The exact command lines you use to build your Lazarus program
 *) An example of Lazarus program that exhibits the problem

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] glibc instead of ulibc ?

[Zoran Djordjevic]

Buildroot is 2012.02. Config, attached. 

Lazarus project is nothing more then simple form- no code. However,
attached is project file and the only unit - all automatically generated 

by IDE.
Tricky part is command for compiling. I do that from IDE - in accordance
with: http://wiki.freepascal.org/Setup_Cross_Compile_For_ARM. 

Of course, I don't expect from someone, not related to Lazarus, to dive 

into that matter, but that was what you asked me (I suppose).
Target libs, that compiler asked me for, I transferred from my NFS 

target folders (mainly <buildroot>/output/target/usr/lib) into ...lazarus/fpc/libcross. Then, 

compiler didn't complain about missing files (as it was without transfering target libs) 

but only error I've mentioned (AT THE MOMENT).? Or to remaind -compiling, passed 

and linking error was:? .../rtl/cprt0.o: In function _start:

(.text+0x4c): undefined reference to __libc_start_main.

Best regards

PS
I may be wrong but GUI programming to me has sense only if
I have friendly environment like VS or Delphi in Windows. 

Learning gtk or Qt functions seems to me very time consuming task instead
of spending time to solve real problem.Lazarus is OK for Linux (,Windows, MacOS...) 

in that sense so I want to try it for ARM cross compiling.



From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Zoran Djordjevic <djdjdjole@yahoo.com> 
Cc: "buildroot at uclibc.org" <buildroot@uclibc.org> 
Sent: Thursday, August 2, 2012 12:42 PM
Subject: Re: [Buildroot] glibc instead of ulibc ?
 
Hello,

Le Thu, 2 Aug 2012 12:38:35 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> Excuse me, Thomas, but I don't know exactly the meaning of? "keeping
> the Buildroot list in Cc", however hope this way is OK.

It is correct. You kept the list in copy of our discussion, which is
good.

> Shortly as possible - I build Tiny X?with Buildroot for ARM and it
> works on target, including your?gtk-demo.Now I try building my own
> simple GUI - gtk program (Lazarus iz Delphi like IDE - it works
> OK?for me?in Linux-?i386 and could be adjusted?for cross compilation
> including ARM). I use it at Ubuntu 11.04. For cross compiling, I
> use?target libraries (X11, pango, ...), built as described. However,
> I probably make some mistake in first pass, and in second attempt
> (few hours ago) the only error reported, AT THE MOMENT, is (like
> first time): undefined refernece?to __libc_start_main. Here
> http://lists.uclibc.org/pipermail/uclibc/2006-June/015659.html?I
> found some statement that uClibc does not have that function (but
> glibc yes). I am aware that this question is maybe more related to
> other forums, but part of it MAYBE to uClibc. So don't bother too
> much with this problem, just hoped that it?was already?recorded
> matter.

If you don't provide all the details needed to reproduce your problem,
there's no way we can help you. So, please provide:

*) Your Buildroot configuration and version
*) The exact command lines you use to build your Lazarus program
*) An example of Lazarus program that exhibits the problem

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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[Buildroot] glibc instead of ulibc ?

[Thomas Petazzoni]

Le Thu, 2 Aug 2012 15:00:07 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> Tricky part is command for compiling. I do that from IDE - in
> accordance with:
> http://wiki.freepascal.org/Setup_Cross_Compile_For_ARM. 

I'm not an expert in this thing, but it seems that those instructions
tell you to build a special ARM compiler for building the Freepascal
code. This looks wrong, as this special compiler doesn't now which C
library is being used on the target.

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] glibc instead of ulibc ?

[Zoran Djordjevic]

Well, if I use "standard" Xorg or Qt I suppose, Free pascal compiler would know
(I suppose that is well known matter in linux - or am I wrong?). But not so sure 
if I use Tiny X (like I do- that's why I tried to built modular Xorg, but not succeeded).
Libraries, which compiler asks me for I put from built ones.
?
Best regards
?
PS I am also suspitious about final success, but I don't know if there is some way to
programm in some RAD GUI environment?(like Lazarus)?and do crosscompiling.


________________________________
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Zoran Djordjevic <djdjdjole@yahoo.com> 
Cc: "buildroot at uclibc.org" <buildroot@uclibc.org> 
Sent: Friday, August 3, 2012 3:06 PM
Subject: Re: [Buildroot] glibc instead of ulibc ?

Le Thu, 2 Aug 2012 15:00:07 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> Tricky part is command for compiling. I do that from IDE - in
> accordance with:
> http://wiki.freepascal.org/Setup_Cross_Compile_For_ARM. 

I'm not an expert in this thing, but it seems that those instructions
tell you to build a special ARM compiler for building the Freepascal
code. This looks wrong, as this special compiler doesn't now which C
library is being used on the target.

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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[Buildroot] glibc instead of ulibc ?

[Eric Bénard]

Hi Zoran,

Le Fri, 3 Aug 2012 07:32:07 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :
> PS I am also suspitious about final success, but I don't know if there is some way to
> programm in some RAD GUI environment?(like Lazarus)?and do crosscompiling.
> 
QTcreator can do that, assuming you have a toolchain with QT
properly integrated, and by providing it a simple helper script
(and having a ssh server with key authentication on your target) you can
even debug from QTCreator using gdb/gdbserver.

Best regards,
Eric

[Buildroot] glibc instead of ulibc ?

[Zoran Djordjevic]

Hello 
?
Regarding problem "undefined refernece?to c", I found,
using "nm" command that this function does not exist in uClibc, and 
it does in glibc (although for i386, but I expect?also in ARM case).Seems to me obvious that some file in my GUI project (as error report 
declares) - ask for __libc_start_main function and certainly not find
it in libc.so (ie uClibc). 
So I intend to build root file system with glibc and want to ask you if?it 
is OK to choose (menuconfig): Toolchain type (CrosstoolNG- toolchain)
and immediately below: CrosstoolNG- C library (glibc) ?
The?other adjustments I would not change. 
What confuses me is that my compiler asked at some moment for?"ld-uClibc.so" 
library and I don't know what would happened if I?build with?glibc.
And at last - do I have to rebuild all if I change toolchain the way I described ?
?
Best regards


________________________________
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Zoran Djordjevic <djdjdjole@yahoo.com> 
Cc: "buildroot at uclibc.org" <buildroot@uclibc.org> 
Sent: Thursday, August 2, 2012 9:42 PM
Subject: Re: [Buildroot] glibc instead of ulibc ?

Hello,

Le Thu, 2 Aug 2012 12:38:35 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> Excuse me, Thomas, but I don't know exactly the meaning of? "keeping
> the Buildroot list in Cc", however hope this way is OK.

It is correct. You kept the list in copy of our discussion, which is
good.

> Shortly as possible - I build Tiny X?with Buildroot for ARM and it
> works on target, including your?gtk-demo.Now I try building my own
> simple GUI - gtk program (Lazarus iz Delphi like IDE - it works
> OK?for me?in Linux-?i386 and could be adjusted?for cross compilation
> including ARM). I use it at Ubuntu 11.04. For cross compiling, I
> use?target libraries (X11, pango, ...), built as described. However,
> I probably make some mistake in first pass, and in second attempt
> (few hours ago) the only error reported, AT THE MOMENT, is (like
> first time): undefined refernece?to __libc_start_main. Here
> http://lists.uclibc.org/pipermail/uclibc/2006-June/015659.html?I
> found some statement that uClibc does not have that function (but
> glibc yes). I am aware that this question is maybe more related to
> other forums, but part of it MAYBE to uClibc. So don't bother too
> much with this problem, just hoped that it?was already?recorded
> matter.

If you don't provide all the details needed to reproduce your problem,
there's no way we can help you. So, please provide:

*) Your Buildroot configuration and version
*) The exact command lines you use to build your Lazarus program
*) An example of Lazarus program that exhibits the problem

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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[Buildroot] glibc instead of ulibc ?

[Thomas Petazzoni]

Hello,

Le Fri, 3 Aug 2012 05:59:26 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> Regarding problem "undefined refernece?to c", I found,
> using "nm" command that this function does not exist in uClibc, and 
> it does in glibc (although for i386, but I expect?also in ARM
> case).Seems to me obvious that some file in my GUI project (as error
> report declares) - ask for __libc_start_main function and certainly
> not find it in libc.so (ie uClibc).

This most likely means that you haven't built your program with the
right compiler. If you had built it with the compiler generated by
Buildroot, which generates programs linked against uClibc, you most
likely wouldn't have this problem.

Please double check how you're building your program.

> So I intend to build root file
> system with glibc and want to ask you if?it is OK to choose
> (menuconfig): Toolchain type (CrosstoolNG- toolchain) and immediately
> below: CrosstoolNG- C library (glibc) ? The?other adjustments I would
> not change.

Sounds good.

> What confuses me is that my compiler asked at some moment
> for?"ld-uClibc.so" library and I don't know what would happened if
> I?build with?glibc.

"at some moment" is way too vague to have any sort of useful technical
discussion, unfortunately.

> And at last - do I have to rebuild all if I change toolchain the way
> I described ?

You have to rebuild everything.

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

[Buildroot] glibc instead of ulibc ?

[Thomas Petazzoni]

Hello,

Again, please don't reply to me directly, but to the list instead.

Le Fri, 3 Aug 2012 07:34:03 -0700 (PDT),
Zoran Djordjevic <djdjdjole@yahoo.com> a ?crit :

> I don't build with Buildroot generated compilerbut with free pascal compiler 
> which is part of Lazarus IDE (beforehend prepeard for ARM?crosscompiling). 

It won't work. You *have* to use the compiler generated by Buildroot,
otherwise you'll face an horrible number of ABI issues and other
compatibility problems.

> And this compiler is the one who asks for (I think) glibc and not uClibc.
> I don't know if I can use GUI IDE and then build with Buildroot compiler. In 
> my case, most likely not - it is Pascal at least. 
> And if I use Buildroot compiler, I must learn gtk and Qt details and spare much 
> time on?graphical designing.

What is the compilation process for Pascal code with Freepascal? Can't
you tell it to use another compiler? Or is this thing a fork from gcc?
Or does it have its own compiler? If you don't look at these in
details, you will never manage to do anything.

That said, you seem to be horrified by GUI development using Qt. Have
you ever tried it for real? It is really simple and nice, so you should
at least give it a try. I think it's a much much better option for
embedded development that this Freepascal/Lazarus stuff.

Best regards,

Thomas
-- 
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com