Log hpx threads on forced shutdown

[Pansysk75]

When an HPX process hangs (usually because some hpx thread hasn't terminated properly), the process is often killed with a termination signal.
In such cases, logging information about any alive hpx threads would really help me in debugging, especially when an issue is hard to reproduce locally.

@hkaiser I can certainly add this if you also think it makes sense, only could you please point me to where exit signals are handled? Thanks!

[hkaiser]

@Pansysk75 Thanks! The termination handlers are here:

hpx/libs/core/runtime_local/src/runtime_local.cpp

Lines 65 to 174 in bc993dd

	namespace hpx {
	///////////////////////////////////////////////////////////////////////////
	void handle_termination(char const* reason)
	{
	if (hpx::threads::coroutines::attach_debugger_on_sigv)
	{
	util::attach_debugger();
	}
	if (hpx::threads::coroutines::diagnostics_on_terminate)
	{
	int const verbosity = hpx::threads::coroutines::exception_verbosity;
	if (verbosity >= 2)
	{
	std::cerr << full_build_string() << "\n";
	}
	#if defined(HPX_HAVE_STACKTRACES)
	if (verbosity >= 1)
	{
	std::size_t const trace_depth =
	util::from_string<std::size_t>(get_config_entry(
	"hpx.trace_depth", HPX_HAVE_THREAD_BACKTRACE_DEPTH));
	std::cerr << "{stack-trace}: " << hpx::util::trace(trace_depth)
	<< "\n";
	}
	#endif
	std::cerr << "{what}: " << (reason ? reason : "Unknown reason")
	<< "\n";
	}
	}
	HPX_CORE_EXPORT BOOL WINAPI termination_handler(DWORD ctrl_type)
	{
	switch (ctrl_type)
	{
	case CTRL_C_EVENT:
	handle_termination("Ctrl-C");
	break;
	case CTRL_BREAK_EVENT:
	handle_termination("Ctrl-Break");
	break;
	case CTRL_CLOSE_EVENT:
	handle_termination("Ctrl-Close");
	break;
	case CTRL_LOGOFF_EVENT:
	handle_termination("Logoff");
	break;
	case CTRL_SHUTDOWN_EVENT:
	handle_termination("Shutdown");
	break;
	default:
	break;
	}
	return FALSE;
	}
	} // namespace hpx
	#else
	#include <signal.h>
	#include <stdlib.h>
	#include <string.h>
	namespace hpx {
	///////////////////////////////////////////////////////////////////////////
	[[noreturn]] HPX_CORE_EXPORT void termination_handler(int signum)
	{
	if (signum != SIGINT &&
	hpx::threads::coroutines::attach_debugger_on_sigv)
	{
	util::attach_debugger();
	}
	if (hpx::threads::coroutines::diagnostics_on_terminate)
	{
	int const verbosity = hpx::threads::coroutines::exception_verbosity;
	char* reason = strsignal(signum);
	if (verbosity >= 2)
	{
	std::cerr << full_build_string() << "\n";
	}
	#if defined(HPX_HAVE_STACKTRACES)
	if (verbosity >= 1)
	{
	std::size_t const trace_depth =
	util::from_string<std::size_t>(get_config_entry(
	"hpx.trace_depth", HPX_HAVE_THREAD_BACKTRACE_DEPTH));
	std::cerr << "{stack-trace}: " << hpx::util::trace(trace_depth)
	<< "\n";
	}
	#endif
	std::cerr << "{what}: " << (reason ? reason : "Unknown reason")
	<< "\n";
	}
	std::abort();
	}
	} // namespace hpx
	#endif

[Pansysk75]

Issue resolved by PR #6340