plucky (3) MPIX_Query_cuda_support.openmpi.3.gz

MPIX_Query_cuda_support - Returns 1 if there is CUDA-aware support and 0 if there is not.

SYNTAX

   C Syntax
          #include <mpi.h>
          #include <mpi-ext.h>

          int MPIX_Query_cuda_support(void)

   Fortran Syntax
       There is no Fortran binding for this function.

   C++ Syntax
       There is no C++ binding for this function.

DESCRIPTION

       This function is part of an Open MPI extension; it is not part of standard MPI.

       This  routine  returns  1  if both the MPI library was built with the NVIDIA CUDA library and the runtime
       supports CUDA buffers.  Otherwise, it returns 0.  This routine must be called after MPI  is  initialized,
       e.g., by a call to MPI_Init(3) or MPI_Init_thread(3).

       Including  the  Open MPI-specific file <mpi-ext.h> will define the C preprocessor macro OMPI_HAVE_MPI_EXT
       to 1.  Otherwise, it will be undefined.  This macro can be used by applications as  a  sentinel  to  know
       whether <mpi-ext.h> has been included or not.

       The  Open  MPI  CUDA  extension is built by default (regardless of whether or not Open MPI was built with
       CUDA support), but could have been disabled by an administrative action.   It  is  therefore  safest  for
       applications  to  check  that the preprocessor macro OMPI_HAVE_MPI_EXT_CUDA is defined and is set to 1 to
       know whether the MPIX_Query_CUDA_support() function is available.  Checking for this macro also  protects
       the  use  of  this  function  when compiling the application with older versions of Open MPI or other MPI
       implementations that do not have this function.

   EXAMPLES
          #include <stdio.h>
          #include <mpi.h>
          #include <mpi-ext.h> /* Needed for CUDA-aware check */

          int main(int argc, char *argv[])
          {
              MPI_Init(&argc, &argv);

              bool happy = false;
          #if defined(OMPI_HAVE_MPI_EXT_CUDA) && OMPI_HAVE_MPI_EXT_CUDA
              happy = (bool) MPIX_Query_cuda_support();
          #endif

              if (happy) {
                  printf("This Open MPI installation has CUDA-aware support.\n");
              } else {
                  printf("This Open MPI installation does not have CUDA-aware support.\n");
              }

              MPI_Finalize();
              return 0;
          }

       SEE ALSO:

          • MPIX_Query_rocm_support

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                        MPIX_QUERY_CUDA_SUPPORT(3)