Natively compile and run parallel Hello World with MPICH_jll MPI in Julia!

mpihello.jl

using StaticCompiler, StaticTools, StaticMPI, MPICH_jll

function mpihello(argc, argv)
    MPI_Init(argc, argv)

    comm = MPI_COMM_WORLD
    world_size, world_rank = MPI_Comm_size(comm), MPI_Comm_rank(comm)

    printf((c"Hello from ", world_rank, c" of ", world_size, c" processors!\n"))
    MPI_Finalize()
end

# Compile
mpilib = joinpath(MPICH_jll.PATH[], "..", "lib")
path = compile_executable(mpihello, (Int, Ptr{Ptr{UInt8}}), "./";
    cflags=`-lmpi -L/$mpilib`
    # -lmpi instructs compiler to link against libmpi.so / libmpi.dylib
    # -L/$mpilib provides path where to find that libmpi
)

# Run
mpiexec = joinpath(MPICH_jll.PATH[], "mpiexec")
run(`$mpiexec -np 8 $path`)