ref: ae0d87a19f53e5e8690e4a41536b5a825a3d9787
dir: /src/libc/stdlib/atexit.c/
#include <stdlib.h>
#include <errno.h>
#undef atexit
int
atexit(void (*fun)(void))
{
if (_exitn == _ATEXIT_MAX) {
errno = ENOMEM;
return -1;
}
_exitf[_exitn++] = fun;
return 0;
}