What: Add support for the MPI-3 MPI_Count datatype and functions: MPI_Get_elements_x, MPI_Status_set_elements_x, MPI_Type_get_extent_x, MPI_Type_get_true_extent_x, and MPI_Type_size_x. This will be CMR'd to 1.7.3 if there are no objections.
Why: MPI_Count is required by the MPI 3.0 standard. This will add another checkmark by MPI 3 support. When: Setting a short timeout of one week (Tues, July 23, 2013). Most of the changes add the new functionality but there are some changes that affect the datatype engine. Details follow. -Nathan Repository @ github: https://github.com/hjelmn/ompi-count.git Relevant commits: General support: https://github.com/hjelmn/ompi-count/commit/db54d13404a241642fa783d5b3cc74edcb1103f2 Fortran support: https://github.com/hjelmn/ompi-count/commit/293adf84be52c2cd8acfe31be19cfe0afe14752d Others: https://github.com/hjelmn/ompi-count/commit/6c6ca8e539da675632c249c891ff93fdbc9d8de8 https://github.com/hjelmn/ompi-count/commit/9638ef1f245f12bb98abbf5f47e1ecfd1a018862 https://github.com/hjelmn/ompi-count/commit/e158aa152d122e554b89498f5a71284ce1361a99 Add support for MPI_Count type and MPI_COUNT datatype and add the required MPI-3 functions MPI_Get_elements_x, MPI_Status_set_elements_x, MPI_Type_get_extent_x, MPI_Type_get_true_extent_x, and MPI_Type_size_x. This commit adds only the C bindings. Fortran bindins will be added in another commit. For now the MPI_Count type is define to have the same size as MPI_Offset. The type is required to be at least as large as MPI_Offset and MPI_Aint. The type was initially intended to be a ssize_t (if it was the same size as a long long) but there were issues compiling romio with that definition (despite the inclusion of stddef.h). I updated the datatype engine to use size_t instead of uint32_t to support large datatypes. This will require some review to make sure that 1) the changes are beneficial, 2) nothing was broken by the change (I doubt anything was), and 3) there are no performance regressions due to this change. George, please look over these changes and let me know if you see anything wrong with my updates to the datatype engine. -Nathan
