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 dict->start=(DNODE *)malloc(sizeof(DNODE)); // error occurs here

 /* DNODE and dict defined as following:

typedef struct _DICTIONARY {
  DNODE *hash[MAX_HASH_SLOT]; // the hash table of slots, each slot points to a DNODE
  DNODE *start;               // start of double link list of DNODES terminated by NULL pointer
  DNODE *end;                 // points to the last DNODE on this list


extern DICTIONARY *dict;

typedef struct _DNODE {
  struct _DNODE  *next;
  struct _DNODE  *prev;
  void    *data;        //  actual data points to URLNODE
  char key[KEY_LENGTH]; //  actual (URL) key 
} __DNODE;

typedef struct _DNODE DNODE;


  dict->start=(DNODE *)malloc(sizeof(DNODE));  //fault~? why?~
  dict->end=(DNODE *)malloc(sizeof(DNODE));


Program received signal SIGSEGV, Segmentation fault.
0x00000000004016e8 in initLists () at crawler.c:202
202 dict->start=(DNODE *)malloc(sizeof(DNODE));

So, why there is seg fault in malloc line~?
Updated 6-Feb-12 22:42pm
Sergey Alexandrovich Kryukov 7-Feb-12 4:29am    
Are you sure this is in this line?
You should also show the definition of dict.
zhaoyilong1 7-Feb-12 4:33am    
I show it, it is a instance of dictionary, OK, let me add the segfault from gdb
Jochen Arndt 7-Feb-12 4:37am    
If the seg fault happens at the indicated line, dict contains probably an invalid address.

As already noted by SA, you should show us how dict is initialized.
zhaoyilong1 7-Feb-12 4:39am    
oh, sure, wait a minute
Jochen Arndt 7-Feb-12 4:48am    
Thanks for the updates. But you should show us where 'extern DICTIONARY *dict' is initialized. That is, the code from the other module where the global variable dict is declared and how it is intialized there (it is a pointer, so there may be something like dict = (DICTIONARY *)malloc(sizeof(DICTIONARY))).

[EDIT]This has been added as the solution found during the comment section conversation.[/EDIT]

If the seg fault happens at the indicated line, dict contains probably an invalid address. This may happen when extern DICTIONARY *dict; is not initialized in the other module.
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Andreas Gieriet 7-Feb-12 5:09am    
I also suspect that the dict pointer is not initialized.
In the initialization code, there is no
dict = (DICTIONARY*)malloc(sizeof(DICTIONARY));


Check 7.19b of the c faq:[^]

Good luck!
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