cc @ZeroIntensity

This introduced a compiler warning:

Python/traceback.c:883:1: warning: ‘dump_pointer’ defined but not used [-Wunused-function]
  883 | dump_pointer(int fd, void *ptr)
      | ^~~~~~~~~~~~

Maybe the function should also be behind an #ifdef?

Python/traceback.c:883:1: warning: ‘dump_pointer’ defined but not used [-Wunused-function]

I wrote #132897 to fix the warning. On which machine/OS did you see the warning?

Aha, now I can see the warning on the WASI build. The configure script says:

checking for backtrace... (cached) no
checking for backtrace_symbols... (cached) no

On which machine/OS did you see the warning?

I saw it on Ubuntu 24.04

I saw it on Ubuntu 24.04

Ok, good to know. I suppose that you miss backtrace_symbol() function. Likely a missing dependency. On Fedora, the /usr/include/execinfo.h header is provided by the glibc-devel package.

Anyway, the warning was fixed by c292f7f. Thanks for the report.

Interesting, I do have the /usr/include/execinfo.h header, but the backtrace_symbol function is missing:

extern int backtrace (void **__array, int __size) __nonnull ((1));

extern char **backtrace_symbols (void *const *__array, int __size)
     __THROW __nonnull ((1));

extern void backtrace_symbols_fd (void *const *__array, int __size, int __fd)
     __THROW __nonnull ((1));

configure.ac looks for these functions:

$ grep backtrace configure.ac -B1
AC_CHECK_HEADERS([execinfo.h link.h dlfcn.h],
                 [AC_CHECK_FUNCS(backtrace backtrace_symbols dladdr1)])

Sorry, it's backtrace_symbols() with S :-)

@ZeroIntensity: By the way, backtrace_symbols test can now removed from configure.ac, it's no longer used, right?

Yup, but I don't know of a system that provides backtrace but not backtrace_symbols.