MFC: r180629, cvs rev. 1.210 in_pcb.c
MFC: r180629, cvs rev. 1.210 in_pcb.c

  ia is a pointer thus use NULL rather then 0 for initialization and
  in comparisons to make this more obvious.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase