[ELDK] 4.2 vs 5.x

[Wolfgang Denk]

Dear Michael,

In message <50A63EBE.4010008 at infoworks.at> you wrote:
>
> I have a question regarding the use of ELDK 5.x.

You are welcome.

> I still use a hardware device containing a ppc85xx board which is
> preloaded by the supplier with a 2.6.24 ELDK 4.2 based Linux.
> 
> Shall/Can I use ELDK 5.x to generate binaries for this platform?
> I have not looked at the newer ELDK versions but I assume that they use
> newer libraries which are not compatible with this old system.

I'm not sure what exactly you mean by "generate binaries".  Depending
on how standard-conforming your code is, you may or may not see some
new compiler warnings or even errors when switching to ELDK 5.2 - this
is the result from moving from GCC 4.2.2 to 4.6.3 with ELDK 5.2 (or
even gcc 4.7.2 with ELDK 5.3); these newer versions of GCC provide not
only much better optimizations, but also much strikter code checking.

Assuming you have well written code, switching to the new tool chain
should be a very smooth operation.  Also, usually you don't have to be
afraid when using the newer tool chain with such an old kwernel
version.  Yes, certain features are not supported by that old kernel
yet, but you should not notice this - your code doesn't use any of
these, as otherwise it would not work with this old kernel now.


But you have to keep in mind that you must rebuild _all_ your code,
i. e. all the libraries and binaries in your root file system.  You
cannot expect to just build one or a few applications with the new
tool chain and run these in the context of your old root file system
using the old libraries.  [Sometimes this may even work, but I would
not rely on it; investing the effort for a full rebuild now is
definitely better spoent time than tracking down any nasty bugs caused
by incompatible library versions later.]

Best regards,

Wolfgang Denk

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