Calling my own Julia functions from C

General Usage
1

Hi everyone,

I have been trying to call a user defined function in Julia in a very simple C code and I am not able too. The code builds up from the most simple Julia function call to what I actually want which is calling a function of my own module and in this last part its where it fails.

The C code is the following:


// very simple C code to call a Julia program 

#include <stdio.h>
#include <julia.h>

int main(){

    jl_init();


    // calling a Julia Base function 
    jl_eval_string("x = sqrt(3.0)");
    jl_eval_string("println(x)");

    // converting types
    jl_value_t *ret = jl_eval_string("sqrt(2.0)");
    double ret_unboxed = jl_unbox_float64(ret);
    printf("sqrt(2.0) in C: %e \n", ret_unboxed);

    // Calling julia functions from Base module
    jl_function_t *func = jl_get_function(jl_base_module, "sqrt");
    jl_value_t *argument = jl_box_float64(2.0);
    jl_value_t *ret2 = jl_call1(func, argument);

    // Calling julia functions from non base modules
    jl_eval_string("using CSV");
    jl_module_t* CSV = (jl_module_t *)jl_eval_string("CSV");
    jl_function_t *write = jl_get_function(CSV, "write");

    // Calling Julia functions from own programs
    jl_eval_string("Base.include(Main, string(/users/miguelborrero/Dropbox/energy_transiitions/Miguel/Code/test.jl))");
    jl_eval_string("using Main.test");
    jl_module_t* test = (jl_module_t *)jl_eval_string("Main.test");
    jl_function_t *test_func = jl_get_function(test, "test_func"); 


    jl_atexit_hook(0);
    return 0;
}

The output is:

Captura de Pantalla 2023-05-10 a la(s) 10.09.33
Captura de Pantalla 2023-05-10 a la(s) 10.09.332662×378 41.8 KB

Also the “module” is:

module test
using CSV, DataFrames
export test_func

function test_func()
    df = DataFrame(x = [], y = [])
    CSV.write("/users/miguelborrero/Dropbox/energy_transiitions/Miguel/Data/test_C.csv", df)
    return 0.0
end

end

A note on compiling the C code:

$ gcc -o test -fPIC -I$JULIA_DIR/include/julia -L$JULIA_DIR/lib -Wl,-rpath,$JULIA_DIR/lib test_jl2.c -ljulia

Any help would be very much appreciated, thanks in advance!
Miguel.