Introduce caml_record_backtraces

The manual suggests calling caml_record_backtrace (which is the
primitive), but this symbol is not declared publicly in the headers. All
occurrences in C, and the use-case detailed in the manual, are for
turning backtraces on, so introduce an actual C function to do this and
remove the declaration of the primitive.

manual/manual/cmds/intf-c.etex

@@ -1712,7 +1712,8 @@ information is available, but the backtrace mechanism needs to be
 turned on programmatically.   This can be achieved from the OCaml side
 by calling "Printexc.record_backtrace true" in the initialization of
 one of the OCaml modules.  This can also be achieved from the C side
-by calling "caml_record_backtrace(Val_int(1));" in the OCaml-C glue code.
+by calling "caml_record_backtraces();" in the OCaml-C glue code.
+("ocaml_receord_backtraces" is declared in "backtrace.h")
 
 \paragraph{Unloading the runtime.}
 

runtime/backtrace.c

@@ -51,6 +51,12 @@ CAMLprim value caml_record_backtrace(value vflag)
   return Val_unit;
 }
 
+CAMLexport void caml_record_backtraces(void)
+{
+  caml_record_backtrace(Val_true);
+  return;
+}
+
 /* Return the status of the backtrace machinery */
 CAMLprim value caml_backtrace_status(value vunit)
 {

runtime/caml/backtrace.h

@@ -16,6 +16,15 @@
 #ifndef CAML_BACKTRACE_H
 #define CAML_BACKTRACE_H
 
+/* [caml_record_backtraces] turns backtrace recording on.
+ * This function can be called at runtime by user-code, or during
+ * initialization if backtraces were requested.
+ *
+ * It might be called before GC initialization, so it shouldn't do OCaml
+ * allocation.
+ */
+CAMLextern void caml_record_backtraces(void);
+
 #ifdef CAML_INTERNALS
 
 #include "mlvalues.h"
@@ -52,7 +61,8 @@
  *   OCaml values of algebraic data-type [Printexc.backtrace_slot]
  */
  /* [Caml_state->backtrace_active] is non zero iff backtraces are recorded.
- * This variable must be changed with [caml_record_backtrace].
+ * This variable must be changed with [caml_record_backtrace] in OCaml or
+ * caml_record_backtraces in C.
  */
 #define caml_backtrace_active (Caml_state_field(backtrace_active))
 /* The [Caml_state->backtrace_buffer] and [Caml_state->backtrace_last_exn]
@@ -89,16 +99,6 @@
      runtimes for raise.
  */
 
-/* [caml_record_backtrace] toggle backtrace recording on and off.
- * This function can be called at runtime by user-code, or during
- * initialization if backtraces were requested.
- *
- * It might be called before GC initialization, so it shouldn't do OCaml
- * allocation.
- */
-CAMLextern value caml_record_backtrace(value vflag);
-
-
 #ifndef NATIVE_CODE
 
 /* Path to the file containing debug information, if any, or NULL. */

runtime/startup_aux.c

@@ -116,7 +116,7 @@ void caml_parse_ocamlrunparam(void)
       switch (*opt++){
       case 'a': scanmult (opt, &p); caml_set_allocation_policy ((intnat) p);
         break;
-      case 'b': scanmult (opt, &p); caml_record_backtrace(Val_bool (p));
+      case 'b': scanmult (opt, &p); if (p) caml_record_backtraces();
         break;
       case 'c': scanmult (opt, &p); caml_cleanup_on_exit = (p != 0); break;
       case 'h': scanmult (opt, &caml_init_heap_wsz); break;

runtime/startup_byt.c

@@ -297,7 +297,7 @@ static int parse_command_line(char_os **argv)
       exit(0);
       break;
     case 'b':
-      caml_record_backtrace(Val_true);
+      caml_record_backtraces();
       break;
     case 'I':
       if (argv[i + 1] != NULL) {