I'm trying to use someone else's Makefile to complile a very simple c++ library. The makefile is as follows:
JNIFLAGS=-O2 -pthread -I/usr/lib/jvm/java-6-sun/include -I/usr/lib/jvm/java-6-sun/include/linux
all:
rm -f ../dist/libUtils.so
g++ $(JNIFLAGS) -c -m32 -o com_markets_utils_dates_NativeTime.o com_markets_utils_dates_NativeTime.cpp
g++ $(JNIFLAGS) -c -m32 -o DateUtil.o DateUtil.cpp
g++ -pthread -m32 -shared -fPIC -o ../dist/libUtils.so DateUtil.cpp
g++ -pthread -m32 -shared -fPIC -o ../dist/libNativeTime.so DateUtil.o com_markets_utils_dates_NativeTime.o
This compiles fine, but the linker complains:
...
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.1/libstdc++.so when searching for -lstdc++
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.1/libstdc++.a when searching for -lstdc++
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.1/libstdc++.so when searching for -lstdc++
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.4.1/libstdc++.a when searching for -lstdc++
/usr/bin/ld: cannot find -lstdc++
collect2: ld returned 1 exit status
make: *** [all] Error 1
FYI, I am on Ubuntu 9.10 64bit.
Posting for future reference, a solution I found was to install g++-multilib. I had the same incompatible problem relating to -lstdc++ on g++ version 4.6.1
On further probing: g++-multilib is a dummy package which installed g++4.6-multilib which in turn installed the appropriate libstdc++.so under the /usr/lib/gcc/x86_64-linux-gnu/4.6/32 folder.