C++ Runtime -

static char instance_memory[sizeof(Logger)]; static uint8_t guard = 0; // 0 = uninitialized, 1 = initializing, 2 = done if (guard == 2) goto done; if (__cxa_guard_acquire(&guard)) new (instance_memory) Logger(); __cxa_guard_release(&guard); __cxa_atexit(destroyer, instance_memory, __dso_handle);

Compiler transforms to:

done: return instance_memory;

static Logger& getLogger() static Logger instance; // thread‑safe initialization return instance; c++ runtime