Usable julia embedding example (julia 0.6.2)

build_and_run.sh

# 0.6.2 in the home directory
#export JULIA_DIR="$HOME/julia-d386e40c17/"
#export JULIA_HOME="$JULIA_DIR/bin"

echo "JULIA_DIR = $JULIA_DIR"
echo "JULIA_HOME = $JULIA_HOME"
#
gcc -o wizbang -fPIC -I$JULIA_DIR/include/julia \
    -std=gnu99                                  \
    -L$JULIA_DIR/lib -L$JULIA_DIR/lib/julia     \
     wizbang.c                                  \
    -l:libjulia.so.0.6.2                        \
    -l:libstdc++.so.6 -l:libLLVM-3.9.so         \
    -DJULIA_ENABLE_THREADING=1                  \
    -lpthread                                   \

LD_LIBRARY_PATH="$JULIA_DIR/lib" ./wizbang

output.txt

START jl_init()... END
sqrt(2.0) = 1.4142135623730951
the size of input is (256, 2)
the size of output is (256, 5)
wiz!

wizbang.c

#include <julia.h>

/* define some plausible constants to make a convincing example */
#define INCHANS    (2)
#define OUTCHANS   (5)
#define NFRAMES  (256)

int main(int argc, char *argv[])
{
    /* required: setup the Julia context */
    printf("START jl_init()...");
    jl_init();
    printf(" END\n");

    /* run Julia commands */
    jl_eval_string("@show sqrt(2.0)");

    /* Create 2D array of float64 type for input/output */
    jl_value_t *array_type = jl_apply_array_type(
        (jl_value_t*)jl_float64_type, 2);
    jl_array_t *input_array = jl_alloc_array_2d(array_type, NFRAMES, INCHANS);
    jl_array_t *output_array = jl_alloc_array_2d(array_type, NFRAMES, OUTCHANS);
    JL_GC_PUSH3(&array_type, &input_array, &output_array);


    jl_eval_string("include(\"wizbang.jl\")");
    jl_function_t *wizbang_func = jl_get_function(jl_main_module, "wizbang");
    jl_call2(wizbang_func, (jl_value_t*)input_array, (jl_value_t*)output_array);

    /* let Julia GC know it can safely GC arrin and arrout */
    JL_GC_POP();

    /* strongly recommended: notify Julia that the
         program is about to terminate. this allows
         Julia time to cleanup pending write requests
         and run all finalizers
    */
    jl_atexit_hook(0);
    return 0;
}

wizbang.jl

function wizbang(inp, outp)
    println("the size of input is $(size(inp))")
    println("the size of output is $(size(outp))")
    println("wiz!")
end