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Old 01-05-2008, 05:26 AM   #1
ruh31
Member
 
Registered: Oct 2004
Location: Germany
Distribution: Ubuntu
Posts: 51

Rep: Reputation: 15
in external function: realloc of array within a struct


Hi everybody!

I am once again having some trouble with re-allocating memory. The basis of the following is this struct:

Code:
typedef struct _MyStruct {
  struct _MyStruct *Father;
  struct _MyStruct *Sons[2];
} MyStruct;

typedef struct _MyStruct2 {
  MyStruct *Structs;
} MyStruct2;
So I have one MyStruct2 in which there is an array of MyStructs in which there are pointers to other MyStructs (a hierarchy).

These variables are important:
Code:
long SIZE;
long INCREASE;
I assign memory and increase memory with the following functions:
Code:
int NEW(MyStruct2 **STRUCT2) {
  *STRUCT2=(MyStruct2 *)malloc(sizeof(MyStruct2));
  (*STRUCT2)->Structs=(MyStruct *)malloc(SIZE*sizeof(MyStruct));
}

int ENLARGE(MyStruct2 **STRUCT2) {
  SIZE=SIZE+INCREASE;
  (*STRUCT2)->Structs=(MyStruct *)realloc((*STRUCT2)->Structs,SIZE*sizeof(MyStruct));
}
My main procedure looks like this:
Code:
int DO(MyStruct2 **STRUCT2, MyStruct *STRUCT) {
  // Fill in father and sons
  // increase counter for used STRUCTS
  // if counter large enough:
  ENLARGE(STRUCT2);
  // and then recursively:
  for (a=0; a<2; a++) DO(STRUCT2,STRUCT->Sons[d];
}

int WHATEVER(MyStruct2 **STRUCT2) {
  NEW(STRUCT2);
  DO(STRUCT2,(*STRUCT2)->Structs);
}
The first function that is called (out of some other code) is WHATEVER.

I know that it may look weird and maybe confusing, but this is the simplest I could do out of my code. I only included the (as I see it) relevant parts for my problem.

As it seems, the program works fine until the second call of ENLARGE. After the second call of ENLARGE, there is a segmentation fault (the pointers do not point to the right structures any more???).

It would be so great if anybody could help me with this problem!

Thanks a lot!
 
Old 01-05-2008, 10:02 AM   #2
ruh31
Member
 
Registered: Oct 2004
Location: Germany
Distribution: Ubuntu
Posts: 51

Original Poster
Rep: Reputation: 15
Anybody has any ideas??? I still have not found out why this is happening and it would be perfect if I finally got it running!

Thanks again!
 
  


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