The atexit function registers the given function to be called at program exit, whether via exit(3) or via return from the programs main. Functions so registered are called in reverse order; no arguments are passed.
These functions must not call exit; if it should be necessary to terminate the process while in such a function, the _exit(2) function should be used. (Alternatively, the function may cause abnormal process termination, for example by calling abort 3.)
At least 32 functions can always be registered, and more are allowed as long as sufficient memory can be allocated.
.Rv -std atexit