]> On Wed, Dec 03, 2003 at 12:19:05PM +0900, Nicolas Cannasse wrote: > > > Is there a reason why stack traces are available only on a crash? I > > > have a project (a distributed OpenPGP keyserver system, > > > http://www.nongnu.org/sks/) that is a long-running daemon. Unexpected > > > errors are caught and logged, but unfortunately, there's no way of > > > getting a stack-trace, since I don't let the exceptions kill the > > > program. This makes debugging much more difficult, and is one of the > > > single largest difficulties I have with ocaml. Is there a technical > > > reason that a bytecode-compiled executable couldn't have access to the > > > stack trace during execution? > > > > I have a partial solution: > [...] > > It's not quite right yet because it only prints out the > > place where the exception was raised (which will be in > > Pervasives if you use failwith), and the place where it > > was caught and printed. Does someone know how to make it > > print the whole stack? > > I think this is because you're adding an additional call to "print", that is > writing on the stack (!). Since you can't write on the stack, you can't call > any ML handler between catching and printing the exception. > You should then have no backtrace.ml and only a mli with : > > external print_stack_strace : unit -> unit = "internal_print" > > the user can then print the exception using a Printexc... after printing the > stack. This doesn't seem to be the problem. When I try it I get basically the same result as before. Here's the modified code: ==== Makefile ==== sources=backtrace.mli backtrace_stubs.c test_bt.ml test_bt: $(sources) ocamlc -custom -g -o test_bt $(sources) clean: rm -f test_bt *.o *.cmo *.cmi ==== backtrace.mli ==== external print : exn -> unit = "internal_print" ==== backtrace_stubs.c ==== #include <caml/mlvalues.h> void print_exception_backtrace(void); value internal_print(value exn) { print_exception_backtrace(); return Val_unit; } ==== test_bt.ml ==== let quux() = raise (Failure "quux has failed") let baz() = quux() let bar() = baz() let foo() = bar() let () = let rec loop = function 0 -> () | k -> begin try foo() with Failure _ as e -> Backtrace.print e end; print_newline(); loop(k-1) in loop 3 -- Issac Trotts ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners