Call JavaScript function from C

Hey,

It’s not pretty clear to me how I can call functions from JavaScript code within my C code.

For example I run this code

int main(int argc, char *argv[]) {
  duk_context *ctx = duk_create_heap_default();
  duk_eval_file(ctx, "test.js");
  duk_destroy_heap(ctx);
  return 0;
}

and inside my test.js is a function like

function GotCalledFromC()
{
   // stuff 
} 

How would it work to call this function in C code ?

Thank you 😃

[fatcerberus]

duk_get_global_string(ctx, "GotCalledFromC");
/* push arguments here */
duk_call(ctx, num_args_pushed);

The function’s return value will then be left on top of the value stack.

[svaarala]

@Memorix101 The getting started processLine() case should be similar, the pieces in the example are:

duk_push_global_object(ctx);
duk_get_prop_string(ctx, -1 /*index*/, "processLine");

duk_push_string(ctx, line);

if (duk_pcall(ctx, 1 /*nargs*/) != 0) {
    printf("Error: %s\n", duk_safe_to_string(ctx, -1));
} else {
    printf("%s\n", duk_safe_to_string(ctx, -1));
}
duk_pop(ctx);  /* pop result/error */

The example uses duk_pcall() to avoid the uncaught error issue mentioned by @fatcerberus above.