Something

boost::timed_mutex::timed_mutex (this=0x660360) at /usr/include/boost/thread/pthread/mutex.hpp:89
89                  int const res=pthread_mutex_init(&m,NULL);
(gdb) p m
$2 = {
  __data = {
    __lock = -178011560, 
    __count = 32767, 
    __owner = -178011560, 
    __nusers = 32767, 
    __kind = 16, 
    __spins = 32767, 
    __list = {
      __prev = 0x660390, 
      __next = 0x0
    }
  }, 
  __size = "X\302c\365\377\177\000\000X\302c\365\377\177\000\000\020\000\000\000\377\177\000\000\220\003f", '\000' <repeats 12 times>, 
  __align = 140737310343768
}
(gdb) p &m
$1 = (pthread_mutex_t *) 0x660360
(gdb) n
90                  if(res)
(gdb) p m
$3 = {
  __data = {
    __lock = 0, 
    __count = 0, 
    __owner = 0, 
    __nusers = 0, 
    __kind = 0, 
    __spins = 0, 
    __list = {
      __prev = 0x0, 
      __next = 0x0
    }
  }, 
  __size = '\000' <repeats 39 times>, 
  __align = 0
}
(gdb) p &m
$4 = (pthread_mutex_t *) 0x660360

.. later ..

boost::timed_mutex::lock (this=0x7ffff6325aff) at /usr/include/boost/thread/pthread/mutex.hpp:125
125                 int res = pthread_mutex_lock(&m);
(gdb) p &m
$5 = (pthread_mutex_t *) 0x7ffff6325aff
(gdb) p m
$6 = {
  __data = {
    __lock = 1316250983, 
    __count = 1701015151, 
    __owner = 1986356224, 
    __nusers = 1684955506, 
    __kind = 1713401199, 
    __spins = 1701603681, 
    __list = {
      __prev = 0x40000010064, 
      __next = 0x500
    }
  }, 
  __size = "getNonce\000devrandom failed\000\001\000\000\004\000\000\000\005\000\000\000\000\000", 
  __align = 7305804444861752679
}
(gdb) n
126                 switch (res) {
(gdb) p res
$8 = 22