Im trying to link the example libcdemo.o but i get the following error

Does anyone know the reason?
Thx in advance

Probably you are trying to link 32bit executable with 64bit linker. There should be some magic options to switch the target CPU.
Also, imho for assembly language programs it is better to use directly the linker ld, instead of the C++ compiler gcc.

Can you please post the cmd for ld, would help me a lot and thanks for your answer.

I am using FASM to generate directly the executable files and hate the linkers since my childhood. So, maybe someone else will be able to help you.

try gcc -m32 ...

I get
/usr/bin/ld: cannot find -lgcc
/usr/bin/ld: cannot find -lgcc_s
collect2: error: ld returned 1 exit status
from
gcc -m32 libcdemo.o -o libcdemo

FYI, depending on your linux distro and whatever package manager you use, there are 32bit compat goods that are needed. I happily run openSUSE Leap, and using its package manager, if I search for gcc I see the following tidbits that would fix your -lgcc:

i | libgcc_s1-32bit | C compiler runtime library | package

There are likely other similar 32bit library requirements but that is the one your output is complaining about.

I have libgcc4.9 installed, it still searches for lgcc, i have linux mint as distro.
I get the same problem with nasm and ld -s -o xy xy.o

What if you install lib32gcc-4.9-dev? I guess it pulls every necessary depending package as well, so don't be scared looking at the list of packages being installed .

I remember this problem. I don't know about Mint, but in Ubuntu you need to install "g++-multilib libc6-dev-i386" before you can use that -m32 switch.