Creating lib with g++ 4.0.1

I'm trying to create a lib with g++ 4.0.1, but it looks for _main (which deliberately isn't in the code). Must I put a _main in there or can I circumvent with some nifty switch? My current command line looks like:

g++ -shared -o mylib.so myobj1.o myobj2.o ...

On a sidenote I'm using g++ powerpc-apple-darwin9, but I'm guessing/hoping that this should be irrelevant. A more complete printout:

$g++ -O0 -ggdb -fPIC -D_DARWIN_C_SOURCE -D_STLP_THREADS -D_POSIX_PTHREAD_SEMANTICS -Istlport/stlport -Iutf8cpp -Ifreealut-1.1.0/include -Iode-0.11.1/include -Iode-0.11.1/ode/src -Iode-0.11.1/ode/src/joints -Iode-0.11.1/OPCODE -Iode-0.11.1/GIMPACT/include -Iode-0.11.1/ou/include -DPOSIX -D_XOPEN_SOURCE=600 -D_DEBUG -D_CONSOLE -DPNG_NO_ASSEMBLER_CODE -DdSingle -DdTLS_ENABLED=1 -DHAVE_CONFIG_H=1 -DLEPRA_WITHOUT_FMOD -framework OpenGL -framework CoreServices -framework OpenAL -DMAC_OS_X_VERSION=1050 -Wno-unknown-pragmas -o myfile.o -c myfile.cpp

$g++ -shared -framework OpenGL -framework AppKit -framework Cocoa -lobjc -lstlport -framework CoreServices -Lstlport/build/lib/obj/gcc/so -L. -Lopenal-soft-1.10.622 -Lfreealut-1.1.0/admin/VisualStudioDotNET/alut -L../Lepra -L../TBC -L../Cure -L../UiLepra -L../UiTBC -L../UiCure -L../Life -framewo开发者_JS百科rk OpenAL -o libThirdParty.so myfile.o
Undefined symbols:
  "_main", referenced from:
      start in crt1.10.5.o
ld: symbol(s) not found
collect2: ld returned 1 exit status
make: *** [libThirdParty.so] Error 1

The solution is to upgrade the compiler. As stated by Adil, 4.1.2 seems to work. Myself, I upgraded to 4.3.4 and that worked great too.