__cxa_atexit(0x402a20, 0, 0, 0x736c69747510072, 0xffffffffffbfb709) = 0
__cxa_atexit — register a function to be called by exit or when a shared library is unloaded
__cxa_atexit() is not in the source standard; it is only in the binary standard.
a snapshot from the binary file.
atexit – register a function to be called at normal process termination