on_exit

Objectives

1. Understand the on_exit exit handler.

Notes

• The last notes were getting too long.
• Still chapter 25
• We can register a handler multiple times.
• atexit has some problems:
  • You do not know the exit status in the call, so you can't take actions based on this.
  • You have no way to pass data to the function.
• int on_exit(typeof(void (int , void *)) *function, void * arg)
  • requires stdlib
  • We are passing a function pointer to a function that
    • takes an int and a void*
    • returns nothing.
  • Returns 0 on success and not zero on failure.
  • Requires some nasty casting.
• See exit2.cpp