Hi everybody,
I'm trying to call a OCaml function from C code. This is the OCaml file:
open Printf
let hello () =
Printf.fprintf stdout "%s" "test"
let () =
let oc = open_out "/tmp/testfile" in
Printf.fprintf oc "test";
close_out oc;
Printf.fprintf stdout "Caml main function\n";
Callback.register "Hello callback" hello;
Printf.fprintf stdout "%s" "Finished with OCaml initialization"
;;
and this is the C file:
#include <stdio.h>
#include <caml/memory.h>
#include <caml/mlvalues.h>
#include <caml/callback.h>
void helloWrapper()
{
static value *closure_f = NULL;
if(closure_f == NULL)
{
printf("1\n");
closure_f = caml_named_value("Hello callback");
printf("2\n");
printf("Closure pointer: %p\n", closure_f);
}
printf("3\n");
caml_callback(*closure_f, Val_unit);
}
int main(int argc, char **argv)
{
caml_main(argv);
printf("calling wrapper\n");
helloWrapper();
printf("Done.");
return 0;
}
Everything seems to work: The file "/tmp/testfile" is created correctly
(so the OCaml function did get called), and the C program ends with
"Done.", *but* nothing is printed from the OCaml fprintf functions.
I am linking the executable with
$(OCAMLOPT) -output-obj test.ml -o test_obj.o
$(CC) -c linkwiththis.c -o linkwiththis.o -I"`$(OCAMLC) -where`"
$(CC) linkwiththis.o test_obj.o $(NATIVECCLIBS) -lasmrun -o
camltestprogram -L"`$(OCAMLC) -where`"
What am I doing wrong - how can I make OCaml print to stdout correctly?
Best regards,
Andreas
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