589 size_t __len) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (3, 4, 5)));
590extern int qecvt_r (long double __value, int __ndigit,
591 int *__restrict __decpt, int *__restrict __sign,
592 char *__restrict __buf, size_t __len)
593 __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (3, 4, 5)));
594extern int qfcvt_r (long double __value, int __ndigit,
595 int *__restrict __decpt, int *__restrict __sign,
596 char *__restrict __buf, size_t __len)
597 __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (3, 4, 5)));
598
599extern int mblen (__const char *__s, size_t __n) __attribute__ ((__nothrow__ , __leaf__)) ;
600extern int mbtowc (wchar_t *__restrict __pwc,
601 __const char *__restrict __s, size_t __n) __attribute__ ((__nothrow__ , __leaf__)) ;
602extern int wctomb (char *__s, wchar_t __wchar) __attribute__ ((__nothrow__ , __leaf__)) ;
603extern size_t mbstowcs (wchar_t *__restrict __pwcs,
604 __const char *__restrict __s, size_t __n) __attribute__ ((__nothrow__ , __leaf__));
605extern size_t wcstombs (char *__restrict __s,
606 __const wchar_t *__restrict __pwcs, size_t __n)
607 __attribute__ ((__nothrow__ , __leaf__));
608
609extern int rpmatch (__const char *__response) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1))) ;
610extern int getsubopt (char **__restrict __optionp,
611 char *__const *__restrict __tokens,
612 char **__restrict __valuep)
613 __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2, 3))) ;
614extern int getloadavg (double __loadavg[], int __nelem)
615 __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
616
617extern int __VERIFIER_nondet_int(void);
618static void fail(void) {
619ERROR:
620 goto ERROR;
621}
622struct node {
623 struct node *next;
624 struct node *prev;
625};
626static struct node* alloc_node(void)
627{
628 struct node *ptr = malloc(sizeof *ptr);
629 if (!ptr)