Hello, When I try to compile mpich in my system, I get the following error. Can someone hint about this? Best, Suraj Making all in tools/topo/hwloc/hwloc make[3]: Entering directory `/root/mpi/mpich-3.0.4/src/pm/hydra/tools/topo/hwloc/hwloc' Making all in src make[4]: Entering directory `/root/mpi/mpich-3.0.4/src/pm/hydra/tools/topo/hwloc/hwloc/src' make[5]: Entering directory `/root/mpi/mpich-3.0.4/src/pm/hydra/tools/topo/hwloc/hwloc/src' CC topology.lo CC traversal.lo CC distances.lo CC components.lo CC bind.lo CC bitmap.lo CC misc.lo CC base64.lo /root/mpi/mpich-3.0.4/src/pm/hydra/tools/topo/hwloc/hwloc/include/private/misc.h(41): catastrophic error: #error directive: "unknown size for unsigned int." #error "unknown size for unsigned int." ^ /root/mpi/mpich-3.0.4/src/pm/hydra/tools/topo/hwloc/hwloc/include/private/misc.h(41): catastrophic error: #error directive: "unknown size for unsigned int." #error "unknown size for unsigned int." ^ /root/mpi/mpich-3.0.4/src/pm/hydra/tools/topo/hwloc/hwloc/include/private/misc.h(41): catastrophic error: #error directive: "unknown size for unsigned int." #error "unknown size for unsigned int." ^ compilation aborted for traversal.c (code 4) compilation aborted for bitmap.c (code 4) compilation aborted for misc.c (code 4)