ref: f812d73e86aa308c373e06a170a1b3ba89ad5cb6
dir: /src/libc/stdlib/atexit.c/
#include <stdlib.h>
#include <errno.h>
#undef atexit
extern void (*_exitf[_ATEXIT_MAX])(void);
extern unsigned _exitn;
int
atexit(void (*fun)(void))
{
if (_exitn == _ATEXIT_MAX) {
errno = ENOMEM;
return -1;
}
_exitf[_exitn++] = fun;
return 0;
}