#5899: expose Printexc.get_callstack. (Cherry-picked 13884, 13885 from trunk.)

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@13886 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02

Changes

@@ -54,10 +54,13 @@ Compilers:
 - PR#5571: incorrect ordinal number in error message
 
 Standard library:
+- PR#5899: expose a way to inspect the current call stack
+  (Printexc.get_callstack)
 - PR#5986: new flag Marshal.Compat_32 for the serialization functions
   (Marshal.to_*), forcing the output to be readable on 32-bit hosts.
 - Add optimized composition operators |> and @@ in Pervasives
 
+
 Runtime system:
 * PR#6019: more efficient implementation of caml_modify() and caml_initialize().
   The new implementations are less lenient than the old ones: now,

stdlib/printexc.ml

@@ -165,3 +165,6 @@ external backtrace_status: unit -> bool = "caml_backtrace_status"
 
 let register_printer fn =
   printers := fn :: !printers
+
+
+external get_callstack: int -> raw_backtrace = "caml_get_current_callstack"

stdlib/printexc.mli

@@ -11,7 +11,7 @@
 (*                                                                     *)
 (***********************************************************************)
 
-(** Facilities for printing exceptions. *)
+(** Facilities for printing exceptions and inspecting current call stack. *)
 
 val to_string: exn -> string
 (** [Printexc.to_string e] returns a string representation of
@@ -99,3 +99,16 @@ type raw_backtrace
 val get_raw_backtrace: unit -> raw_backtrace
 val print_raw_backtrace: out_channel -> raw_backtrace -> unit
 val raw_backtrace_to_string: raw_backtrace -> string
+
+
+(** {6 Current call stack} *)
+
+val get_callstack: int -> raw_backtrace
+
+(** [Printexc.get_callstack n] returns a description of the top of the
+    call stack on the current program point (for the current thread),
+    with at most [n] entries.  (Note: this function is not related to
+    exceptions at all, despite being part of the [Printexc] module.)
+
+    @since 4.01.0
+*)