1 files changed, 70 insertions, 0 deletions
diff --git a/otherlibs/labltk/support/cltkCaml.c b/otherlibs/labltk/support/cltkCaml.c
new file mode 100644
index 0000000000..bb87ba5bdd
--- /dev/null
+++ b/otherlibs/labltk/support/cltkCaml.c
@@ -0,0 +1,70 @@
+#include <tcl.h>
+#include <tk.h>
+#include <caml/mlvalues.h>
+#include <caml/callback.h>
+#include "camltk.h"
+
+value * tkerror_exn = NULL;
+value * handler_code = NULL;
+
+/* The Tcl command for evaluating callback in Caml */
+int CamlCBCmd(clientdata, interp, argc, argv)
+     ClientData clientdata;
+     Tcl_Interp *interp;
+     int argc;
+     char *argv[];
+{
+  CheckInit();
+
+  /* Assumes no result */
+  Tcl_SetResult(interp, NULL, NULL);
+  if (argc >= 2) {
+    int id;
+    if (Tcl_GetInt(interp, argv[1], &id) != TCL_OK)
+      return TCL_ERROR;
+    callback2(*handler_code,Val_int(id),copy_string_list(argc - 2,&argv[2]));
+    /* Never fails (Caml would have raised an exception) */
+    /* but result may have been set by callback */
+    return TCL_OK;
+  }
+  else
+    return TCL_ERROR;
+}
+
+/* Callbacks are always of type _ -> unit, to simplify storage
+ * But a callback can nevertheless return something (to Tcl) by
+ * using the following. TCL_VOLATILE ensures that Tcl will make
+ * a copy of the string
+ */
+value camltk_return (v) /* ML */
+     value v;
+{
+  CheckInit();
+
+  Tcl_SetResult(cltclinterp, String_val(v), TCL_VOLATILE);
+  return Val_unit;
+}
+
+/* Note: raise_with_string WILL copy the error message */
+void tk_error(errmsg)
+     char *errmsg;
+{
+  raise_with_string(*tkerror_exn, errmsg);
+}
+
+
+/* The initialisation of the C global variables pointing to Caml values
+   must be made accessible from Caml, so that we are sure that it *always*
+   takes place during loading of the protocol module
+ */
+
+value camltk_init(v) /* ML */
+     value v;
+{
+  /* Initialize the Caml pointers */
+  if (tkerror_exn == NULL)
+    tkerror_exn = caml_named_value("tkerror");
+  if (handler_code == NULL)
+    handler_code = caml_named_value("camlcb");
+  return Val_unit;
+}