g++ compile error: undefined reference to a shared library function which exists

Question

I recently installed the hdf5 library on an ubuntu machine, and am now having trouble linking to the exported functions. I wrote a simple test script re

Answer 1

This is not a bug. See C++ shared library undefined reference to `FooClass::SayHello()'

"Recent versions of GCC reuqire that you put the object files and libraries in the order that they depend on each other ..."

Answer 2

You forgot to put -lhdf5 in the compile command. Also, there's no need for -l:$HOME/hdf5/lib/libhdf5.so

This should work: $ g++ -Wl,-rpath,$HOME/hdf5/lib -I$HOME/hdf5/include -L$HOME/hdf5/lib -lhdf5 readHDF5.cpp

Answer 3

Ok, solved. The issue was in the placement of the -lhdf5 in the compile command. Apparently -lhdf5 should be placed after readHDF.cpp. For instance g++ -Wl,-rpath=$HOME/hdf5/lib -L$HOME/hdf5/lib -I$HOME/hdf5/include readHDF.cpp -lhdf5 will compile with no problems, but g++ -Wl,-rpath=$HOME/hdf5/lib -L$HOME/hdf5/lib -I$HOME/hdf5/include -lhdf5 readHDF.cpp will fail with the undefined reference errors. Interestingly, this was only a problem for Ubuntu 12.04, as both compile commands worked for Ubuntu 10.04.

Found the answer with explanation at this post:

undefined reference to symbol even when nm indicates that this symbol is present

I guess placing -lXXX after the script is safer practice.