Data commit

Task/Use-another-language-to-call-a-function/OCaml/use-another-language-to-call-a-function-1.ocaml

@@ -0,0 +1,36 @@
+#include <stdio.h>
+#include <string.h>
+#include <caml/mlvalues.h>
+#include <caml/callback.h>
+
+extern int Query (char * Data, size_t * Length)
+{
+   static value * closure_f = NULL;
+   if (closure_f == NULL) {
+       closure_f = caml_named_value("Query function cb");
+   }
+   value ret = caml_callback(*closure_f, Val_unit);
+   *Length = Int_val(Field(ret, 1));
+   strncpy(Data, String_val(Field(ret, 0)), *Length);
+   return 1;
+}
+
+int main (int argc, char * argv [])
+{
+   char     Buffer [1024];
+   unsigned Size = 0;
+
+   caml_main(argv);  /* added from the original main */
+
+   if (0 == Query (Buffer, &Size))
+   {
+      printf ("failed to call Query\n");
+   }
+   else
+   {
+      char * Ptr = Buffer;
+      printf("size: %d\n", Size);
+      while (Size-- > 0) putchar (*Ptr++);
+      putchar ('\n');
+   }
+}

Task/Use-another-language-to-call-a-function/OCaml/use-another-language-to-call-a-function-2.ocaml

@@ -0,0 +1,8 @@
+let caml_query () =
+  let s = "Here am I" in
+  (s, String.length s)
+;;
+
+let () =
+  Callback.register "Query function cb" caml_query;
+;;