none none wrote:
> I have tried to produce executable code for my embedded linux system
with the cross-gcc
> when I try to run it on my target system I get the following error:
> bash$./hello_world
> ./hello_world: error in loading shared libraries
> : undefined symbol: __libc_start_main
> I know that I am supposed to export to my target system the dynamic
libraries I need.
No, no ! Totally vice versa - you should copy the runtimes and
development parts from your
target system onto the cross host before starting to build the cross GCC
there! If you would
build a native GCC onto your target system, it would use the '/lib',
'/usr/include' and '/usr/lib'
stuff on it... Totally in the same way the cross GCC would need to use
this same stuff when
creating executables for this target system. So you only need to build
binutils and GCC for
your cross-host, they must run there meanwhile the target C library is
something which was
produced for the target system, not for the host system!
If the target system hasn't any C library for it yet, then you must
produce it (on the cross host)!
> The problem is that I cannot find the libraries neither in
crosstools directory nor in eldk dir.
> Where are they?
Just look at '/lib' (the runtimes) and '/usr/lib' (development
libraries) or the "install CD"s for your
embedded Linux (the development parts aren't surely installed)! Please
look 'bash' with 'ldd' in
your Linux target system :
bash$ ldd /bin/bash
A 'bash' in a Linux distro lists quite a lot runtimes, so in order to
run bash, one should have them
all already installed! When you could run 'bash' then you must have
some runtimes installed!
> Did not they created when the crosstools or eldk installed? Do I
have to install or make anything
> else I have not understood?
You haven't understood that a crosstoolchain will be made to produce
apps for the target system,
not for something else! The goal in 'crosstool' and 'eldk' is to create
the target system from scratch
using the produced crosstoolchain, and the self-made runtime C libraries
will be installed onto the
target system (which hadn't anything yet) !
> Furthermore when I give ldd hello_world in my host platform I get the
message:
> not a dynamic executable
> where in my target system I get
> libc.so.6 => /lib/libc.so.6 (0x30000000)
> /lib/ld.so.1 => /lib/ld.so.1 (0x08000000)
So you ALREADY HAVE the required '/lib/libc.so.6' and '/lib/ld.so.1' on
your target system! But
you DIDN'T USE THEM in your crosstoolchain although for all sanity you
should have done so!
Then the apps produced there would have been linked against these
linktime/runtime libraries. The
crosstoolchain you made was targeted for SOMETHING ELSE, and uses some
other target libs,
so there is no guarantee that the executables made with it could run on
your target system :-(
