[Buildroot] Questions related to "Incorrect selection of the C library" error

[Buildroot] Questions related to "Incorrect selection of the C library" error

[stl]

Hello all,

I am trying to port Buildroot for a new architecture and I am facing
the following error when I build it:

Checking external toolchain settings
Incorrect selection of the C library

The following lib (ld*-uClibc.so.*) is missing in my /lib/ dir.
Where does this lib come from?

In my .config, I have selected BR2_TOOLCHAIN_EXTERNAL=y
and I have set the path for my toolchain, and the prefix.

But where can I set the path for my installed uClibc directory?
( /usr/<arch>-linux-uclibc )

Thanks in advance for your help.
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[Buildroot] Questions related to "Incorrect selection of the C library" error

[Thomas Petazzoni]

Le Wed, 14 Sep 2011 10:16:19 +0200,
stl <st.lambert02@gmail.com> a ?crit :

> I am trying to port Buildroot for a new architecture and I am facing
> the following error when I build it:
> 
> Checking external toolchain settings
> Incorrect selection of the C library
> 
> The following lib (ld*-uClibc.so.*) is missing in my /lib/ dir.
> Where does this lib come from?

From the external toolchain.

> In my .config, I have selected BR2_TOOLCHAIN_EXTERNAL=y
> and I have set the path for my toolchain, and the prefix.
> 
> But where can I set the path for my installed uClibc directory?
> ( /usr/<arch>-linux-uclibc )

In the toolchain menu:
 * Select "External toolchain" as Toolchain type
 * Select "Custom toolchain" as Toolchain
 * Put the path of your toolchain in Toolchain path

Regards,

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

[Buildroot] Questions related to "Incorrect selection of the C library" error

[Arnout Vandecappelle]

On Wednesday 14 September 2011 11:52:17, Thomas Petazzoni wrote:
> > The following lib (ld*-uClibc.so.*) is missing in my lib dir.
> > Where does this lib come from?
> 
> From the external toolchain.
> 
> > In my .config, I have selected BR2_TOOLCHAIN_EXTERNAL=y
> > and I have set the path for my toolchain, and the prefix.
> >
> > 
> >
> > But where can I set the path for my installed uClibc directory?
> > ( /usr/<arch>-linux-uclibc )
> 
> In the toolchain menu:
>  * Select "External toolchain" as Toolchain type
>  * Select "Custom toolchain" as Toolchain
>  * Put the path of your toolchain in Toolchain path

 What Thomas means is: you have to install uClibc in the same place as the 
cross compiler.  

Cross-compiler and libc (and various other things like dynamic library loader 
and debugger) are intimately linked. Together they are called the toolchain.  

 Regards,
 Arnout

-- 
Arnout Vandecappelle                               arnout at mind be
Senior Embedded Software Architect                 +32-16-286540
Essensium/Mind                                     http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium                BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
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[Buildroot] Questions related to "Incorrect selection of the C library" error

[stl]

Thomas and Arnout, thanks for your answers.

Effectively, my port of uClibc is not installed in the same directory than
my toolchain.
Because, the version of the toolchain I use is compiled with newlib as C
library, instead of uClibc.

And my problem with the ld-uclibc.so.* comes from I have not done anything
yet that deals with
dynamic linker in my port of uClibc.

It seems that some work remains to be done...

Ok I going to dig all these things.

Thanks again for your help.
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[Buildroot] Questions related to "Incorrect selection of the C library" error

[Thomas Petazzoni]

Le Thu, 15 Sep 2011 11:20:44 +0200,
stl <st.lambert02@gmail.com> a ?crit :

> Effectively, my port of uClibc is not installed in the same directory
> than my toolchain.
> Because, the version of the toolchain I use is compiled with newlib
> as C library, instead of uClibc.
> 
> And my problem with the ld-uclibc.so.* comes from I have not done
> anything yet that deals with
> dynamic linker in my port of uClibc.
> 
> It seems that some work remains to be done...

With a bit tuning, Buildroot can work with a toolchain that does not
support shared libraries (so you can postpone the work on the dynamic
linker later on). But it needs to be a real toolchain, not a bare-metal
compiler on one side and the C library on the other side.

So before diving into the dynamic linking stuff and shared libraries, I
would recommend you to work on getting a proper toolchain built, either
with Buildroot or Crosstool-NG (I would suggest the latter). If you
have a working binutils/gcc/uClibc port, integrating the support for
your arch in Crosstool-NG should not be very complicated.

Regards,

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