strange linker warnings

[Antonio Coralles <noche.suapie@xxxxxxxxx>]

I'm using gcc-3.3.5 and are currently working on a C++ project called 
duty-roaster [http://sourceforge.net/projects/duty-roaster]. When i 
compile the program with the '-g' flag, it compiles and links without a 
single warning. But when i remove the -g option, i get lot's of messages 
from the linker, like this one

/usr/lib/gcc-lib/i686-pc-linux-gnu/3.3.5-20050130/../../../../i686-pc-linux-gnu/bin/ld: 
`.gnu.linkonce.t._ZN5boost9date_time11int_adapterIxE12from_specialENS0_14special_valuesE' 
referenced in section `.rodata' of 
shared/lib_shared.a(lib_shared_a-simpleutils.o): defined in discarded 
section 
`.gnu.linkonce.t._ZN5boost9date_time11int_adapterIxE12from_specialENS0_14special_valuesE' 
of shared/lib_shared.a(lib_shared_a-simpleutils.o)

Despite these messages the program finally links and works fine. Any 
explanations ?

Thanks, Matthias Langer