Use Caml macros for variables

src/qt/oboy.cpp

@@ -3,6 +3,7 @@
 #include <caml/mlvalues.h>
 #include <caml/callback.h>
 #include <caml/alloc.h>
+#include <caml/memory.h>
 #include <caml/misc.h>
 #include <caml/osdeps.h>
 
@@ -11,40 +12,57 @@ OBoy::OBoy(QObject *parent) : QObject(parent)
 
 }
 
+// https://caml.inria.fr/pub/docs/manual-ocaml/intfc.html
+// http://www.mega-nerd.com/erikd/Blog/CodeHacking/Ocaml/calling_ocaml.html
+
 QString OBoy::name() const
 {
+    CAMLparam0();
+
     value * closure_f = caml_named_value("oboy_name");
     if (closure_f == nullptr) {
+        CAMLdrop;
         return QString("<Unreachable>");
     }
 
     const char *str = String_val(caml_callback(*closure_f, Val_unit));
+    CAMLdrop;
     return QString(str);
 }
 
 QString OBoy::version() const
 {
+    CAMLparam0();
+
     value * closure_f = caml_named_value("oboy_version");
     if (closure_f == nullptr) {
+        CAMLdrop;
         return QString("<Unreachable>");
     }
 
     const char *str = String_val(caml_callback(*closure_f, Val_unit));
+    CAMLdrop;
     return QString(str);
 }
 
 bool OBoy::load(const QString &path)
 {
+    CAMLparam0();
+    CAMLlocal1(ocaml_path) ;
+
     value * closure_f = caml_named_value("oboy_load");
     if (closure_f == nullptr) {
+        CAMLdrop;
         return false;
     }
 
     QString truncated(path);
     truncated.remove(0, 7); // remove file://
     QByteArray ba = truncated.toLocal8Bit();
-    value ocaml_path = caml_copy_string_of_os(ba.data());
+
+    ocaml_path = caml_copy_string_of_os(ba.data());
 
     const bool success = Bool_val(caml_callback(*closure_f, ocaml_path));
+    CAMLdrop;
     return success;
 }