queue_false-unreach-call.i

extern int __VERIFIER_nondet_int(void);
extern void __VERIFIER_error() __attribute__ ((__noreturn__));

typedef unsigned char __u_char;
typedef unsigned short int __u_short;
typedef unsigned int __u_int;
typedef unsigned long int __u_long;
typedef signed char __int8_t;
typedef unsigned char __uint8_t;
typedef signed short int __int16_t;
typedef unsigned short int __uint16_t;
typedef signed int __int32_t;
typedef unsigned int __uint32_t;
typedef signed long int __int64_t;
typedef unsigned long int __uint64_t;
typedef long int __quad_t;
typedef unsigned long int __u_quad_t;
typedef unsigned long int __dev_t;
typedef unsigned int __uid_t;
typedef unsigned int __gid_t;
typedef unsigned long int __ino_t;
typedef unsigned long int __ino64_t;
typedef unsigned int __mode_t;
typedef unsigned long int __nlink_t;
typedef long int __off_t;
typedef long int __off64_t;
typedef int __pid_t;
typedef struct { int __val[2]; } __fsid_t;
typedef long int __clock_t;
typedef unsigned long int __rlim_t;
typedef unsigned long int __rlim64_t;
typedef unsigned int __id_t;
typedef long int __time_t;
typedef unsigned int __useconds_t;
typedef long int __suseconds_t;
typedef int __daddr_t;
typedef long int __swblk_t;
typedef int __key_t;
typedef int __clockid_t;
typedef void * __timer_t;
typedef long int __blksize_t;
typedef long int __blkcnt_t;
typedef long int __blkcnt64_t;
typedef unsigned long int __fsblkcnt_t;
typedef unsigned long int __fsblkcnt64_t;
typedef unsigned long int __fsfilcnt_t;
typedef unsigned long int __fsfilcnt64_t;
typedef long int __ssize_t;
typedef __off64_t __loff_t;
typedef __quad_t *__qaddr_t;
typedef char *__caddr_t;
typedef long int __intptr_t;
typedef unsigned int __socklen_t;
typedef long unsigned int size_t;

typedef __time_t time_t;


struct timespec
  {
    __time_t tv_sec;
    long int tv_nsec;
  };
typedef __pid_t pid_t;
struct sched_param
  {
    int __sched_priority;
  };


struct __sched_param
  {
    int __sched_priority;
  };
typedef unsigned long int __cpu_mask;
typedef struct
{
  __cpu_mask __bits[1024 / (8 * sizeof (__cpu_mask))];
} cpu_set_t;

extern int __sched_cpucount (size_t __setsize, const cpu_set_t *__setp)
  __attribute__ ((__nothrow__ , __leaf__));
extern cpu_set_t *__sched_cpualloc (size_t __count) __attribute__ ((__nothrow__ , __leaf__)) ;
extern void __sched_cpufree (cpu_set_t *__set) __attribute__ ((__nothrow__ , __leaf__));


extern int sched_setparam (__pid_t __pid, __const struct sched_param *__param)
     __attribute__ ((__nothrow__ , __leaf__));
extern int sched_getparam (__pid_t __pid, struct sched_param *__param) __attribute__ ((__nothrow__ , __leaf__));
extern int sched_setscheduler (__pid_t __pid, int __policy,
          __const struct sched_param *__param) __attribute__ ((__nothrow__ , __leaf__));
extern int sched_getscheduler (__pid_t __pid) __attribute__ ((__nothrow__ , __leaf__));
extern int sched_yield (void) __attribute__ ((__nothrow__ , __leaf__));
extern int sched_get_priority_max (int __algorithm) __attribute__ ((__nothrow__ , __leaf__));
extern int sched_get_priority_min (int __algorithm) __attribute__ ((__nothrow__ , __leaf__));
extern int sched_rr_get_interval (__pid_t __pid, struct timespec *__t) __attribute__ ((__nothrow__ , __leaf__));



typedef __clock_t clock_t;


typedef __clockid_t clockid_t;



typedef __timer_t timer_t;

struct tm
{
  int tm_sec;
  int tm_min;
  int tm_hour;
  int tm_mday;
  int tm_mon;
  int tm_year;
  int tm_wday;
  int tm_yday;
  int tm_isdst;
  long int tm_gmtoff;
  __const char *tm_zone;
};


struct itimerspec
  {
    struct timespec it_interval;
    struct timespec it_value;
  };
struct sigevent;

extern clock_t clock (void) __attribute__ ((__nothrow__ , __leaf__));
extern time_t time (time_t *__timer) __attribute__ ((__nothrow__ , __leaf__));
extern double difftime (time_t __time1, time_t __time0)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__const__));
extern time_t mktime (struct tm *__tp) __attribute__ ((__nothrow__ , __leaf__));
extern size_t strftime (char *__restrict __s, size_t __maxsize,
   __const char *__restrict __format,
   __const struct tm *__restrict __tp) __attribute__ ((__nothrow__ , __leaf__));

typedef struct __locale_struct
{
  struct __locale_data *__locales[13];
  const unsigned short int *__ctype_b;
  const int *__ctype_tolower;
  const int *__ctype_toupper;
  const char *__names[13];
} *__locale_t;
typedef __locale_t locale_t;
extern size_t strftime_l (char *__restrict __s, size_t __maxsize,
     __const char *__restrict __format,
     __const struct tm *__restrict __tp,
     __locale_t __loc) __attribute__ ((__nothrow__ , __leaf__));

extern struct tm *gmtime (__const time_t *__timer) __attribute__ ((__nothrow__ , __leaf__));
extern struct tm *localtime (__const time_t *__timer) __attribute__ ((__nothrow__ , __leaf__));

extern struct tm *gmtime_r (__const time_t *__restrict __timer,
       struct tm *__restrict __tp) __attribute__ ((__nothrow__ , __leaf__));
extern struct tm *localtime_r (__const time_t *__restrict __timer,
          struct tm *__restrict __tp) __attribute__ ((__nothrow__ , __leaf__));

extern char *asctime (__const struct tm *__tp) __attribute__ ((__nothrow__ , __leaf__));
extern char *ctime (__const time_t *__timer) __attribute__ ((__nothrow__ , __leaf__));

extern char *asctime_r (__const struct tm *__restrict __tp,
   char *__restrict __buf) __attribute__ ((__nothrow__ , __leaf__));
extern char *ctime_r (__const time_t *__restrict __timer,
        char *__restrict __buf) __attribute__ ((__nothrow__ , __leaf__));
extern char *__tzname[2];
extern int __daylight;
extern long int __timezone;
extern char *tzname[2];
extern void tzset (void) __attribute__ ((__nothrow__ , __leaf__));
extern int daylight;
extern long int timezone;
extern int stime (__const time_t *__when) __attribute__ ((__nothrow__ , __leaf__));
extern time_t timegm (struct tm *__tp) __attribute__ ((__nothrow__ , __leaf__));
extern time_t timelocal (struct tm *__tp) __attribute__ ((__nothrow__ , __leaf__));
extern int dysize (int __year) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__const__));
extern int nanosleep (__const struct timespec *__requested_time,
        struct timespec *__remaining);
extern int clock_getres (clockid_t __clock_id, struct timespec *__res) __attribute__ ((__nothrow__ , __leaf__));
extern int clock_gettime (clockid_t __clock_id, struct timespec *__tp) __attribute__ ((__nothrow__ , __leaf__));
extern int clock_settime (clockid_t __clock_id, __const struct timespec *__tp)
     __attribute__ ((__nothrow__ , __leaf__));
extern int clock_nanosleep (clockid_t __clock_id, int __flags,
       __const struct timespec *__req,
       struct timespec *__rem);
extern int clock_getcpuclockid (pid_t __pid, clockid_t *__clock_id) __attribute__ ((__nothrow__ , __leaf__));
extern int timer_create (clockid_t __clock_id,
    struct sigevent *__restrict __evp,
    timer_t *__restrict __timerid) __attribute__ ((__nothrow__ , __leaf__));
extern int timer_delete (timer_t __timerid) __attribute__ ((__nothrow__ , __leaf__));
extern int timer_settime (timer_t __timerid, int __flags,
     __const struct itimerspec *__restrict __value,
     struct itimerspec *__restrict __ovalue) __attribute__ ((__nothrow__ , __leaf__));
extern int timer_gettime (timer_t __timerid, struct itimerspec *__value)
     __attribute__ ((__nothrow__ , __leaf__));
extern int timer_getoverrun (timer_t __timerid) __attribute__ ((__nothrow__ , __leaf__));

typedef unsigned long int pthread_t;
typedef union
{
  char __size[56];
  long int __align;
} pthread_attr_t;
typedef struct __pthread_internal_list
{
  struct __pthread_internal_list *__prev;
  struct __pthread_internal_list *__next;
} __pthread_list_t;
typedef union
{
  struct __pthread_mutex_s
  {
    int __lock;
    unsigned int __count;
    int __owner;
    unsigned int __nusers;
    int __kind;
    int __spins;
    __pthread_list_t __list;
  } __data;
  char __size[40];
  long int __align;
} pthread_mutex_t;
typedef union
{
  char __size[4];
  int __align;
} pthread_mutexattr_t;
typedef union
{
  struct
  {
    int __lock;
    unsigned int __futex;
    __extension__ unsigned long long int __total_seq;
    __extension__ unsigned long long int __wakeup_seq;
    __extension__ unsigned long long int __woken_seq;
    void *__mutex;
    unsigned int __nwaiters;
    unsigned int __broadcast_seq;
  } __data;
  char __size[48];
  __extension__ long long int __align;
} pthread_cond_t;
typedef union
{
  char __size[4];
  int __align;
} pthread_condattr_t;
typedef unsigned int pthread_key_t;
typedef int pthread_once_t;
typedef union
{
  struct
  {
    int __lock;
    unsigned int __nr_readers;
    unsigned int __readers_wakeup;
    unsigned int __writer_wakeup;
    unsigned int __nr_readers_queued;
    unsigned int __nr_writers_queued;
    int __writer;
    int __shared;
    unsigned long int __pad1;
    unsigned long int __pad2;
    unsigned int __flags;
  } __data;
  char __size[56];
  long int __align;
} pthread_rwlock_t;
typedef union
{
  char __size[8];
  long int __align;
} pthread_rwlockattr_t;
typedef volatile int pthread_spinlock_t;
typedef union
{
  char __size[32];
  long int __align;
} pthread_barrier_t;
typedef union
{
  char __size[4];
  int __align;
} pthread_barrierattr_t;
typedef long int __jmp_buf[8];
enum
{
  PTHREAD_CREATE_JOINABLE,
  PTHREAD_CREATE_DETACHED
};
enum
{
  PTHREAD_MUTEX_TIMED_NP,
  PTHREAD_MUTEX_RECURSIVE_NP,
  PTHREAD_MUTEX_ERRORCHECK_NP,
  PTHREAD_MUTEX_ADAPTIVE_NP
  ,
  PTHREAD_MUTEX_NORMAL = PTHREAD_MUTEX_TIMED_NP,
  PTHREAD_MUTEX_RECURSIVE = PTHREAD_MUTEX_RECURSIVE_NP,
  PTHREAD_MUTEX_ERRORCHECK = PTHREAD_MUTEX_ERRORCHECK_NP,
  PTHREAD_MUTEX_DEFAULT = PTHREAD_MUTEX_NORMAL
};
enum
{
  PTHREAD_MUTEX_STALLED,
  PTHREAD_MUTEX_STALLED_NP = PTHREAD_MUTEX_STALLED,
  PTHREAD_MUTEX_ROBUST,
  PTHREAD_MUTEX_ROBUST_NP = PTHREAD_MUTEX_ROBUST
};
enum
{
  PTHREAD_RWLOCK_PREFER_READER_NP,
  PTHREAD_RWLOCK_PREFER_WRITER_NP,
  PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,
  PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP
};
enum
{
  PTHREAD_INHERIT_SCHED,
  PTHREAD_EXPLICIT_SCHED
};
enum
{
  PTHREAD_SCOPE_SYSTEM,
  PTHREAD_SCOPE_PROCESS
};
enum
{
  PTHREAD_PROCESS_PRIVATE,
  PTHREAD_PROCESS_SHARED
};
struct _pthread_cleanup_buffer
{
  void (*__routine) (void *);
  void *__arg;
  int __canceltype;
  struct _pthread_cleanup_buffer *__prev;
};
enum
{
  PTHREAD_CANCEL_ENABLE,
  PTHREAD_CANCEL_DISABLE
};
enum
{
  PTHREAD_CANCEL_DEFERRED,
  PTHREAD_CANCEL_ASYNCHRONOUS
};

extern int pthread_create (pthread_t *__restrict __newthread,
      __const pthread_attr_t *__restrict __attr,
      void *(*__start_routine) (void *),
      void *__restrict __arg) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1, 3)));
extern void pthread_exit (void *__retval) __attribute__ ((__noreturn__));
extern int pthread_join (pthread_t __th, void **__thread_return);
extern int pthread_detach (pthread_t __th) __attribute__ ((__nothrow__ , __leaf__));
extern pthread_t pthread_self (void) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__const__));
extern int pthread_equal (pthread_t __thread1, pthread_t __thread2) __attribute__ ((__nothrow__ , __leaf__));
extern int pthread_attr_init (pthread_attr_t *__attr) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_destroy (pthread_attr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_getdetachstate (__const pthread_attr_t *__attr,
     int *__detachstate)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_setdetachstate (pthread_attr_t *__attr,
     int __detachstate)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_getguardsize (__const pthread_attr_t *__attr,
          size_t *__guardsize)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_setguardsize (pthread_attr_t *__attr,
          size_t __guardsize)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_getschedparam (__const pthread_attr_t *__restrict
           __attr,
           struct sched_param *__restrict __param)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_setschedparam (pthread_attr_t *__restrict __attr,
           __const struct sched_param *__restrict
           __param) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_getschedpolicy (__const pthread_attr_t *__restrict
     __attr, int *__restrict __policy)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_setschedpolicy (pthread_attr_t *__attr, int __policy)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_getinheritsched (__const pthread_attr_t *__restrict
      __attr, int *__restrict __inherit)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_setinheritsched (pthread_attr_t *__attr,
      int __inherit)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_getscope (__const pthread_attr_t *__restrict __attr,
      int *__restrict __scope)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_setscope (pthread_attr_t *__attr, int __scope)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_getstackaddr (__const pthread_attr_t *__restrict
          __attr, void **__restrict __stackaddr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2))) __attribute__ ((__deprecated__));
extern int pthread_attr_setstackaddr (pthread_attr_t *__attr,
          void *__stackaddr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1))) __attribute__ ((__deprecated__));
extern int pthread_attr_getstacksize (__const pthread_attr_t *__restrict
          __attr, size_t *__restrict __stacksize)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_attr_setstacksize (pthread_attr_t *__attr,
          size_t __stacksize)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_attr_getstack (__const pthread_attr_t *__restrict __attr,
      void **__restrict __stackaddr,
      size_t *__restrict __stacksize)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2, 3)));
extern int pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
      size_t __stacksize) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_setschedparam (pthread_t __target_thread, int __policy,
      __const struct sched_param *__param)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (3)));
extern int pthread_getschedparam (pthread_t __target_thread,
      int *__restrict __policy,
      struct sched_param *__restrict __param)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (2, 3)));
extern int pthread_setschedprio (pthread_t __target_thread, int __prio)
     __attribute__ ((__nothrow__ , __leaf__));
extern int pthread_once (pthread_once_t *__once_control,
    void (*__init_routine) (void)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_setcancelstate (int __state, int *__oldstate);
extern int pthread_setcanceltype (int __type, int *__oldtype);
extern int pthread_cancel (pthread_t __th);
extern void pthread_testcancel (void);
typedef struct
{
  struct
  {
    __jmp_buf __cancel_jmp_buf;
    int __mask_was_saved;
  } __cancel_jmp_buf[1];
  void *__pad[4];
} __pthread_unwind_buf_t __attribute__ ((__aligned__));
struct __pthread_cleanup_frame
{
  void (*__cancel_routine) (void *);
  void *__cancel_arg;
  int __do_it;
  int __cancel_type;
};
extern void __pthread_register_cancel (__pthread_unwind_buf_t *__buf)
     ;
extern void __pthread_unregister_cancel (__pthread_unwind_buf_t *__buf)
  ;
extern void __pthread_unwind_next (__pthread_unwind_buf_t *__buf)
     __attribute__ ((__noreturn__))
     __attribute__ ((__weak__))
     ;
struct __jmp_buf_tag;
extern int __sigsetjmp (struct __jmp_buf_tag *__env, int __savemask) __attribute__ ((__nothrow__ , __leaf__));
extern int pthread_mutex_init (pthread_mutex_t *__mutex,
          __const pthread_mutexattr_t *__mutexattr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutex_destroy (pthread_mutex_t *__mutex)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutex_trylock (pthread_mutex_t *__mutex)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutex_lock (pthread_mutex_t *__mutex)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutex_timedlock (pthread_mutex_t *__restrict __mutex,
        __const struct timespec *__restrict
        __abstime) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_mutex_unlock (pthread_mutex_t *__mutex)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutex_getprioceiling (__const pthread_mutex_t *
      __restrict __mutex,
      int *__restrict __prioceiling)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_mutex_setprioceiling (pthread_mutex_t *__restrict __mutex,
      int __prioceiling,
      int *__restrict __old_ceiling)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 3)));
extern int pthread_mutex_consistent (pthread_mutex_t *__mutex)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutexattr_init (pthread_mutexattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutexattr_destroy (pthread_mutexattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutexattr_getpshared (__const pthread_mutexattr_t *
      __restrict __attr,
      int *__restrict __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_mutexattr_setpshared (pthread_mutexattr_t *__attr,
      int __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutexattr_gettype (__const pthread_mutexattr_t *__restrict
          __attr, int *__restrict __kind)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_mutexattr_settype (pthread_mutexattr_t *__attr, int __kind)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutexattr_getprotocol (__const pthread_mutexattr_t *
       __restrict __attr,
       int *__restrict __protocol)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_mutexattr_setprotocol (pthread_mutexattr_t *__attr,
       int __protocol)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutexattr_getprioceiling (__const pthread_mutexattr_t *
          __restrict __attr,
          int *__restrict __prioceiling)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_mutexattr_setprioceiling (pthread_mutexattr_t *__attr,
          int __prioceiling)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_mutexattr_getrobust (__const pthread_mutexattr_t *__attr,
     int *__robustness)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_mutexattr_setrobust (pthread_mutexattr_t *__attr,
     int __robustness)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlock_init (pthread_rwlock_t *__restrict __rwlock,
    __const pthread_rwlockattr_t *__restrict
    __attr) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlock_destroy (pthread_rwlock_t *__rwlock)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlock_rdlock (pthread_rwlock_t *__rwlock)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlock_tryrdlock (pthread_rwlock_t *__rwlock)
  __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict __rwlock,
           __const struct timespec *__restrict
           __abstime) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_rwlock_wrlock (pthread_rwlock_t *__rwlock)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlock_trywrlock (pthread_rwlock_t *__rwlock)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlock_timedwrlock (pthread_rwlock_t *__restrict __rwlock,
           __const struct timespec *__restrict
           __abstime) __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_rwlock_unlock (pthread_rwlock_t *__rwlock)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlockattr_init (pthread_rwlockattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlockattr_destroy (pthread_rwlockattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlockattr_getpshared (__const pthread_rwlockattr_t *
       __restrict __attr,
       int *__restrict __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_rwlockattr_setpshared (pthread_rwlockattr_t *__attr,
       int __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_rwlockattr_getkind_np (__const pthread_rwlockattr_t *
       __restrict __attr,
       int *__restrict __pref)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_rwlockattr_setkind_np (pthread_rwlockattr_t *__attr,
       int __pref) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_cond_init (pthread_cond_t *__restrict __cond,
         __const pthread_condattr_t *__restrict
         __cond_attr) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_cond_destroy (pthread_cond_t *__cond)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_cond_signal (pthread_cond_t *__cond)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_cond_broadcast (pthread_cond_t *__cond)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_cond_wait (pthread_cond_t *__restrict __cond,
         pthread_mutex_t *__restrict __mutex)
     __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_cond_timedwait (pthread_cond_t *__restrict __cond,
       pthread_mutex_t *__restrict __mutex,
       __const struct timespec *__restrict
       __abstime) __attribute__ ((__nonnull__ (1, 2, 3)));
extern int pthread_condattr_init (pthread_condattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_condattr_destroy (pthread_condattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_condattr_getpshared (__const pthread_condattr_t *
     __restrict __attr,
     int *__restrict __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_condattr_setpshared (pthread_condattr_t *__attr,
     int __pshared) __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_condattr_getclock (__const pthread_condattr_t *
          __restrict __attr,
          __clockid_t *__restrict __clock_id)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_condattr_setclock (pthread_condattr_t *__attr,
          __clockid_t __clock_id)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_spin_init (pthread_spinlock_t *__lock, int __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_spin_destroy (pthread_spinlock_t *__lock)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_spin_lock (pthread_spinlock_t *__lock)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_spin_trylock (pthread_spinlock_t *__lock)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_spin_unlock (pthread_spinlock_t *__lock)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_barrier_init (pthread_barrier_t *__restrict __barrier,
     __const pthread_barrierattr_t *__restrict
     __attr, unsigned int __count)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_barrier_destroy (pthread_barrier_t *__barrier)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_barrier_wait (pthread_barrier_t *__barrier)
     __attribute__ ((__nothrow__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_barrierattr_init (pthread_barrierattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_barrierattr_destroy (pthread_barrierattr_t *__attr)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_barrierattr_getpshared (__const pthread_barrierattr_t *
        __restrict __attr,
        int *__restrict __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1, 2)));
extern int pthread_barrierattr_setpshared (pthread_barrierattr_t *__attr,
        int __pshared)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_key_create (pthread_key_t *__key,
          void (*__destr_function) (void *))
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (1)));
extern int pthread_key_delete (pthread_key_t __key) __attribute__ ((__nothrow__ , __leaf__));
extern void *pthread_getspecific (pthread_key_t __key) __attribute__ ((__nothrow__ , __leaf__));
extern int pthread_setspecific (pthread_key_t __key,
    __const void *__pointer) __attribute__ ((__nothrow__ , __leaf__)) ;
extern int pthread_getcpuclockid (pthread_t __thread_id,
      __clockid_t *__clock_id)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__nonnull__ (2)));
extern int pthread_atfork (void (*__prepare) (void),
      void (*__parent) (void),
      void (*__child) (void)) __attribute__ ((__nothrow__ , __leaf__));


struct _IO_FILE;

typedef struct _IO_FILE FILE;


typedef struct _IO_FILE __FILE;
typedef struct
{
  int __count;
  union
  {
    unsigned int __wch;
    char __wchb[4];
  } __value;
} __mbstate_t;
typedef struct
{
  __off_t __pos;
  __mbstate_t __state;
} _G_fpos_t;
typedef struct
{
  __off64_t __pos;
  __mbstate_t __state;
} _G_fpos64_t;
typedef int _G_int16_t __attribute__ ((__mode__ (__HI__)));
typedef int _G_int32_t __attribute__ ((__mode__ (__SI__)));
typedef unsigned int _G_uint16_t __attribute__ ((__mode__ (__HI__)));
typedef unsigned int _G_uint32_t __attribute__ ((__mode__ (__SI__)));
typedef __builtin_va_list __gnuc_va_list;
struct _IO_jump_t; struct _IO_FILE;
typedef void _IO_lock_t;
struct _IO_marker {
  struct _IO_marker *_next;
  struct _IO_FILE *_sbuf;
  int _pos;
};
enum __codecvt_result
{
  __codecvt_ok,
  __codecvt_partial,
  __codecvt_error,
  __codecvt_noconv
};
struct _IO_FILE {
  int _flags;
  char* _IO_read_ptr;
  char* _IO_read_end;
  char* _IO_read_base;
  char* _IO_write_base;
  char* _IO_write_ptr;
  char* _IO_write_end;
  char* _IO_buf_base;
  char* _IO_buf_end;
  char *_IO_save_base;
  char *_IO_backup_base;
  char *_IO_save_end;
  struct _IO_marker *_markers;
  struct _IO_FILE *_chain;
  int _fileno;
  int _flags2;
  __off_t _old_offset;
  unsigned short _cur_column;
  signed char _vtable_offset;
  char _shortbuf[1];
  _IO_lock_t *_lock;
  __off64_t _offset;
  void *__pad1;
  void *__pad2;
  void *__pad3;
  void *__pad4;
  size_t __pad5;
  int _mode;
  char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
};
typedef struct _IO_FILE _IO_FILE;
struct _IO_FILE_plus;
extern struct _IO_FILE_plus _IO_2_1_stdin_;
extern struct _IO_FILE_plus _IO_2_1_stdout_;
extern struct _IO_FILE_plus _IO_2_1_stderr_;
typedef __ssize_t __io_read_fn (void *__cookie, char *__buf, size_t __nbytes);
typedef __ssize_t __io_write_fn (void *__cookie, __const char *__buf,
     size_t __n);
typedef int __io_seek_fn (void *__cookie, __off64_t *__pos, int __w);
typedef int __io_close_fn (void *__cookie);
extern int __underflow (_IO_FILE *);
extern int __uflow (_IO_FILE *);
extern int __overflow (_IO_FILE *, int);
extern int _IO_getc (_IO_FILE *__fp);
extern int _IO_putc (int __c, _IO_FILE *__fp);
extern int _IO_feof (_IO_FILE *__fp) __attribute__ ((__nothrow__ , __leaf__));
extern int _IO_ferror (_IO_FILE *__fp) __attribute__ ((__nothrow__ , __leaf__));
extern int _IO_peekc_locked (_IO_FILE *__fp);
extern void _IO_flockfile (_IO_FILE *) __attribute__ ((__nothrow__ , __leaf__));
extern void _IO_funlockfile (_IO_FILE *) __attribute__ ((__nothrow__ , __leaf__));
extern int _IO_ftrylockfile (_IO_FILE *) __attribute__ ((__nothrow__ , __leaf__));
extern int _IO_vfscanf (_IO_FILE * __restrict, const char * __restrict,
   __gnuc_va_list, int *__restrict);
extern int _IO_vfprintf (_IO_FILE *__restrict, const char *__restrict,
    __gnuc_va_list);
extern __ssize_t _IO_padn (_IO_FILE *, int, __ssize_t);
extern size_t _IO_sgetn (_IO_FILE *, void *, size_t);
extern __off64_t _IO_seekoff (_IO_FILE *, __off64_t, int, int);
extern __off64_t _IO_seekpos (_IO_FILE *, __off64_t, int);
extern void _IO_free_backup_area (_IO_FILE *) __attribute__ ((__nothrow__ , __leaf__));
typedef __gnuc_va_list va_list;
typedef __off_t off_t;
typedef __ssize_t ssize_t;

typedef _G_fpos_t fpos_t;

extern struct _IO_FILE *stdin;
extern struct _IO_FILE *stdout;
extern struct _IO_FILE *stderr;

extern int remove (__const char *__filename) __attribute__ ((__nothrow__ , __leaf__));
extern int rename (__const char *__old, __const char *__new) __attribute__ ((__nothrow__ , __leaf__));

extern int renameat (int __oldfd, __const char *__old, int __newfd,
       __const char *__new) __attribute__ ((__nothrow__ , __leaf__));

extern FILE *tmpfile (void) ;
extern char *tmpnam (char *__s) __attribute__ ((__nothrow__ , __leaf__)) ;

extern char *tmpnam_r (char *__s) __attribute__ ((__nothrow__ , __leaf__)) ;
extern char *tempnam (__const char *__dir, __const char *__pfx)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__malloc__)) ;

extern int fclose (FILE *__stream);
extern int fflush (FILE *__stream);

extern int fflush_unlocked (FILE *__stream);

extern FILE *fopen (__const char *__restrict __filename,
      __const char *__restrict __modes) ;
extern FILE *freopen (__const char *__restrict __filename,
        __const char *__restrict __modes,
        FILE *__restrict __stream) ;

extern FILE *fdopen (int __fd, __const char *__modes) __attribute__ ((__nothrow__ , __leaf__)) ;
extern FILE *fmemopen (void *__s, size_t __len, __const char *__modes)
  __attribute__ ((__nothrow__ , __leaf__)) ;
extern FILE *open_memstream (char **__bufloc, size_t *__sizeloc) __attribute__ ((__nothrow__ , __leaf__)) ;

extern void setbuf (FILE *__restrict __stream, char *__restrict __buf) __attribute__ ((__nothrow__ , __leaf__));
extern int setvbuf (FILE *__restrict __stream, char *__restrict __buf,
      int __modes, size_t __n) __attribute__ ((__nothrow__ , __leaf__));

extern void setbuffer (FILE *__restrict __stream, char *__restrict __buf,
         size_t __size) __attribute__ ((__nothrow__ , __leaf__));
extern void setlinebuf (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__));

extern int fprintf (FILE *__restrict __stream,
      __const char *__restrict __format, ...);
extern int printf (__const char *__restrict __format, ...);
extern int sprintf (char *__restrict __s,
      __const char *__restrict __format, ...) __attribute__ ((__nothrow__));
extern int vfprintf (FILE *__restrict __s, __const char *__restrict __format,
       __gnuc_va_list __arg);
extern int vprintf (__const char *__restrict __format, __gnuc_va_list __arg);
extern int vsprintf (char *__restrict __s, __const char *__restrict __format,
       __gnuc_va_list __arg) __attribute__ ((__nothrow__));


extern int snprintf (char *__restrict __s, size_t __maxlen,
       __const char *__restrict __format, ...)
     __attribute__ ((__nothrow__)) __attribute__ ((__format__ (__printf__, 3, 4)));
extern int vsnprintf (char *__restrict __s, size_t __maxlen,
        __const char *__restrict __format, __gnuc_va_list __arg)
     __attribute__ ((__nothrow__)) __attribute__ ((__format__ (__printf__, 3, 0)));

extern int vdprintf (int __fd, __const char *__restrict __fmt,
       __gnuc_va_list __arg)
     __attribute__ ((__format__ (__printf__, 2, 0)));
extern int dprintf (int __fd, __const char *__restrict __fmt, ...)
     __attribute__ ((__format__ (__printf__, 2, 3)));

extern int fscanf (FILE *__restrict __stream,
     __const char *__restrict __format, ...) ;
extern int scanf (__const char *__restrict __format, ...) ;
extern int sscanf (__const char *__restrict __s,
     __const char *__restrict __format, ...) __attribute__ ((__nothrow__ , __leaf__));
extern int fscanf (FILE *__restrict __stream, __const char *__restrict __format, ...) __asm__ ("" "__isoc99_fscanf") ;
extern int scanf (__const char *__restrict __format, ...) __asm__ ("" "__isoc99_scanf") ;
extern int sscanf (__const char *__restrict __s, __const char *__restrict __format, ...) __asm__ ("" "__isoc99_sscanf") __attribute__ ((__nothrow__ , __leaf__));


extern int vfscanf (FILE *__restrict __s, __const char *__restrict __format,
      __gnuc_va_list __arg)
     __attribute__ ((__format__ (__scanf__, 2, 0))) ;
extern int vscanf (__const char *__restrict __format, __gnuc_va_list __arg)
     __attribute__ ((__format__ (__scanf__, 1, 0))) ;
extern int vsscanf (__const char *__restrict __s,
      __const char *__restrict __format, __gnuc_va_list __arg)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__format__ (__scanf__, 2, 0)));
extern int vfscanf (FILE *__restrict __s, __const char *__restrict __format, __gnuc_va_list __arg) __asm__ ("" "__isoc99_vfscanf")
     __attribute__ ((__format__ (__scanf__, 2, 0))) ;
extern int vscanf (__const char *__restrict __format, __gnuc_va_list __arg) __asm__ ("" "__isoc99_vscanf")
     __attribute__ ((__format__ (__scanf__, 1, 0))) ;
extern int vsscanf (__const char *__restrict __s, __const char *__restrict __format, __gnuc_va_list __arg) __asm__ ("" "__isoc99_vsscanf") __attribute__ ((__nothrow__ , __leaf__))
     __attribute__ ((__format__ (__scanf__, 2, 0)));


extern int fgetc (FILE *__stream);
extern int getc (FILE *__stream);
extern int getchar (void);

extern int getc_unlocked (FILE *__stream);
extern int getchar_unlocked (void);
extern int fgetc_unlocked (FILE *__stream);

extern int fputc (int __c, FILE *__stream);
extern int putc (int __c, FILE *__stream);
extern int putchar (int __c);

extern int fputc_unlocked (int __c, FILE *__stream);
extern int putc_unlocked (int __c, FILE *__stream);
extern int putchar_unlocked (int __c);
extern int getw (FILE *__stream);
extern int putw (int __w, FILE *__stream);

extern char *fgets (char *__restrict __s, int __n, FILE *__restrict __stream)
     ;
extern char *gets (char *__s) ;

extern __ssize_t __getdelim (char **__restrict __lineptr,
          size_t *__restrict __n, int __delimiter,
          FILE *__restrict __stream) ;
extern __ssize_t getdelim (char **__restrict __lineptr,
        size_t *__restrict __n, int __delimiter,
        FILE *__restrict __stream) ;
extern __ssize_t getline (char **__restrict __lineptr,
       size_t *__restrict __n,
       FILE *__restrict __stream) ;

extern int fputs (__const char *__restrict __s, FILE *__restrict __stream);
extern int puts (__const char *__s);
extern int ungetc (int __c, FILE *__stream);
extern size_t fread (void *__restrict __ptr, size_t __size,
       size_t __n, FILE *__restrict __stream) ;
extern size_t fwrite (__const void *__restrict __ptr, size_t __size,
        size_t __n, FILE *__restrict __s);

extern size_t fread_unlocked (void *__restrict __ptr, size_t __size,
         size_t __n, FILE *__restrict __stream) ;
extern size_t fwrite_unlocked (__const void *__restrict __ptr, size_t __size,
          size_t __n, FILE *__restrict __stream);

extern int fseek (FILE *__stream, long int __off, int __whence);
extern long int ftell (FILE *__stream) ;
extern void rewind (FILE *__stream);

extern int fseeko (FILE *__stream, __off_t __off, int __whence);
extern __off_t ftello (FILE *__stream) ;

extern int fgetpos (FILE *__restrict __stream, fpos_t *__restrict __pos);
extern int fsetpos (FILE *__stream, __const fpos_t *__pos);


extern void clearerr (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__));
extern int feof (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__)) ;
extern int ferror (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__)) ;

extern void clearerr_unlocked (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__));
extern int feof_unlocked (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__)) ;
extern int ferror_unlocked (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__)) ;

extern void perror (__const char *__s);

extern int sys_nerr;
extern __const char *__const sys_errlist[];
extern int fileno (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__)) ;
extern int fileno_unlocked (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__)) ;
extern FILE *popen (__const char *__command, __const char *__modes) ;
extern int pclose (FILE *__stream);
extern char *ctermid (char *__s) __attribute__ ((__nothrow__ , __leaf__));
extern void flockfile (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__));



extern int ftrylockfile (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__)) ;


extern void funlockfile (FILE *__stream) __attribute__ ((__nothrow__ , __leaf__));


extern void __assert_fail (__const char *__assertion, __const char *__file,
      unsigned int __line, __const char *__function)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__noreturn__));
extern void __assert_perror_fail (int __errnum, __const char *__file,
      unsigned int __line,
      __const char *__function)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__noreturn__));
extern void __assert (const char *__assertion, const char *__file, int __line)
     __attribute__ ((__nothrow__ , __leaf__)) __attribute__ ((__noreturn__));

typedef struct {
    int element[(20)];
    int head;
    int tail;
    int amount;
} QType;
pthread_mutex_t m;
int __VERIFIER_nondet_int();
int stored_elements[(20)];
_Bool enqueue_flag, dequeue_flag;
QType queue;
void init(QType *q)
{
  q->head=0;
  q->tail=0;
  q->amount=0;
}
int empty(QType * q)
{
  if (q->head == q->tail)
  {
    printf("queue is empty\n");
    return (-1);
  }
  else
    return 0;
}
int full(QType * q)
{
  if (q->amount == (20))
  {
 printf("queue is full\n");
 return (-2);
  }
  else
    return 0;
}
int enqueue(QType *q, int x)
{
  q->element[q->tail] = x;
  q->amount++;
  if (q->tail == (20))
  {
    q->tail = 1;
  }
  else
  {
    q->tail++;
  }
  return 0;
}
int dequeue(QType *q)
{
  int x;
  x = q->element[q->head];
  q->amount--;
  if (q->head == (20))
  {
    q->head = 1;
  }
  else
    q->head++;
  return x;
}
void *t1(void *arg)
{
  int value, i;
  pthread_mutex_lock(&m);
  value = __VERIFIER_nondet_int();
  if (enqueue(&queue,value)) {
    goto ERROR;
  }
  stored_elements[0]=value;
  if (empty(&queue)) {
    goto ERROR;
  }
  pthread_mutex_unlock(&m);
  for(i=0; i<((20)-1); i++)
  {
    pthread_mutex_lock(&m);
    if (enqueue_flag)
    {
      value = __VERIFIER_nondet_int();
      enqueue(&queue,value);
      stored_elements[i+1]=value;
      enqueue_flag=(0);
      dequeue_flag=(1);
    }
    pthread_mutex_unlock(&m);
  }
  return ((void *)0);
  ERROR: __VERIFIER_error();
}
void *t2(void *arg)
{
  int i;
  for(i=0; i<(20); i++)
  {
    pthread_mutex_lock(&m);
    if (dequeue_flag)
    {
      if (!dequeue(&queue)==stored_elements[i]) {
        ERROR: __VERIFIER_error();
      }
      dequeue_flag=(0);
      enqueue_flag=(1);
    }
    pthread_mutex_unlock(&m);
  }
  return ((void *)0);
}
int main(void)
{
  pthread_t id1, id2;
  enqueue_flag=(1);
  dequeue_flag=(0);
  init(&queue);
  if (!empty(&queue)==(-1)) {
    ERROR: __VERIFIER_error();
    goto ERROR;
  }
  pthread_mutex_init(&m, 0);
  pthread_create(&id1, ((void *)0), t1, &queue);
  pthread_create(&id2, ((void *)0), t2, &queue);
  pthread_join(id1, ((void *)0));
  pthread_join(id2, ((void *)0));
  return 0;
}