How to print out gc logs?

Learning
1

I want to see the caml_gc_log messages but I don’t know how to make that happened.

Compiled on clang 13.0.0, ./configure --prefix=something I would expect the logs to be printed to stderr but I don’t see them when running with ocamlrun.

#ifdef CAML_INTERNALS

/* GC flags and messages */

extern atomic_uintnat caml_verb_gc;

void caml_gc_log (char *, ...)
#ifdef __GNUC__
  __attribute__ ((format (printf, 1, 2)))
#endif
;

Here’s the definition. I think clang has gnu extensions, so that shouldn’t be a problem. Also, I tried compiling with CFLAGS=-DCAML_INTERNALS but that gave macro redefined errors. Not sure what’s the problem

2

Have you already tried, either programmatically enabling using Gc.set or setting the environment variable OCAMLRUNPARAM="v=???"?