I get the following compile warnings … looking at bond.h it does declare BondSM as a struct at the bottom and a friend class also, but then BondSM_sm.h now calls it a class. This all seems odd. 

Shouldn't the declaration in bond.h be a class?

// Internal use only
struct BondSM << change  to class??
{
  BondSM(bond::Bond *b_) : b(b_) {}
  void Connected();
  void SisterDied();
  void Death();
  void Heartbeat();
  void StartDying();

private:
  bond::Bond *b;
};

-----------------------------------
Error snippet:

Scanning dependencies of target rospack_genmsg_libexe
[  0%] Built target rospack_genmsg_libexe
Scanning dependencies of target rosbuild_precompile
[  0%] Built target rosbuild_precompile
Scanning dependencies of target bondcpp
[ 33%] Building CXX object CMakeFiles/bondcpp.dir/src/timeout.o
[ 66%] Building CXX object CMakeFiles/bondcpp.dir/src/bond.o
In file included from /Users/kevin/ros_sandbox/stacks/bond_core/bondcpp/src/bond.cpp:32:
/Users/kevin/ros_sandbox/stacks/bond_core/bondcpp/include/bondcpp/bond.h:186:1: warning: 
      'BondSM' defined as a struct here but previously declared as a class
      [-Wmismatched-tags]
struct BondSM
^
/Users/kevin/ros_sandbox/stacks/bond_core/bondcpp/include/BondSM_sm.h:25:1: note: 
      did you mean struct here?
class BondSM;
^~~~~
struct
1 warning generated.
[100%] Building CXX object CMakeFiles/bondcpp.dir/src/BondSM_sm.o
In file included from /Users/kevin/ros_sandbox/stacks/bond_core/bondcpp/src/BondSM_sm.cpp:8:
/Users/kevin/ros_sandbox/stacks/bond_core/bondcpp/include/bondcpp/bond.h:186:1: warning: 
      'BondSM' defined as a struct here but previously declared as a class
      [-Wmismatched-tags]
struct BondSM
^
/Users/kevin/ros_sandbox/stacks/bond_core/bondcpp/include/BondSM_sm.h:25:1: note: 
      did you mean struct here?
class BondSM;
^~~~~
struct
1 warning generated.
Linking CXX shared library ../lib/libbondcpp.dylib
clang: warning: argument unused during compilation: '-pthread'
[100%] Built target bondcpp