main_arena是什么东西？

[syouweiz]

#0 0x0086a159 in main_arena () from /lib/libc.so.6
#1 0x0806751a in fun_name_a (this=0xa7537e0, r=ReleaseMe,
p=0xa83c6a0) at filename.cxx:1945
#2 0x0806db99 in fun_name_b (pB=0xa7537e0)
at filename.cxx:2184
#3 0x008a343b in start_thread () from /lib/libpthread.so.0
#4 0x007fafde in clone () from /lib/libc.so.6

[猫已经找不回了]

晕,这是什么?

[独孤过儿]

这是malloc()实现过程中的一个结构体，具体代码如下：

/* There are several instances of this struct ("arenas") in this
   malloc.  If you are adapting this malloc in a way that does NOT use
   a static or mmapped malloc_state, you MUST explicitly zero-fill it
   before using. This malloc relies on the property that malloc_state
   is initialized to all zeroes (as is true of C statics).  */

static struct malloc_state main_arena;

/*
   ----------- Internal state representation and initialization -----------
*/

struct malloc_state {
  /* Serialize access.  */
  mutex_t mutex;

  /* Flags (formerly in max_fast).  */
  int flags;

#if THREAD_STATS
  /* Statistics for locking.  Only used if THREAD_STATS is defined.  */
  long stat_lock_direct, stat_lock_loop, stat_lock_wait;
#endif

  /* Fastbins */
  mfastbinptr      fastbins[NFASTBINS];

  /* Base of the topmost chunk -- not otherwise kept in a bin */
  mchunkptr        top;

  /* The remainder from the most recent split of a small request */
  mchunkptr        last_remainder;

  /* Normal bins packed as described above */
  mchunkptr        bins[NBINS * 2 - 2];

  /* Bitmap of bins */
  unsigned int     binmap[BINMAPSIZE];

  /* Linked list */
  struct malloc_state *next;

  /* Memory allocated from the system in this arena.  */
  INTERNAL_SIZE_T system_mem;
  INTERNAL_SIZE_T max_system_mem;
};