Memory Management

[rasdfasfd]

G'Day,
Just a quick query on memory management.
I have a dynamic array of a particular struct.

struct myStruct
  int stuff;
  ...
  void * anotherStruct;
}

As the code suggests the field anotherStruct can point to a number of different structs. Each of these structs may contain zero or more pointers to allocated memory. Rather than having a complex cleanup routine I though this might be a better way.

struct allocatedMemory {
  //array of pointers
  void ** memPtrs[];
  int numElements;
}

struct diffStruct1 {
  struct allocatedMemory am;
  char * ptr1;
  unsigned char * ptr2;
}

and more diffStructs something like above.

Then, whenever I fill out one of the diffStructs I also fill out the allocatedMemory struct contained within it with an array of all the pointers to allocated memory in the diffStruct.

ds.am.memPtrs = malloc(2 * sizeof(void *) );
ds.am.memPtrs[0] = ds.ptr1;
ds.am.memPtrs[1] = ds.ptr2;
ds.am.numElements = 2;

Then when it comes time to cleanup it is as easy as:

//loop through array of my structs
struct allocatedMemory *t = (myStruct[index]).anotherStruct
for (int x = 0;x< t->numElements;t++) {
  free(t->memPtrs[x])
}

Does anyone have comments on this approach? Is it portable? Is there other ways?

[master5001]

Like anything else there are sacrifices. It looks like you are sacrificing speed for ease of use (for this applicatation it isn't a bad trade-off). I also noticed that you aren't actually allocating memory for each struct. I am confident that you just didn't post this part of the code but if you aren't be sure to do something like.

ds.ptr1 = malloc(buffer_size);

Although it is a good trade-off between easy/safe code and speed it is not a good to have large objects. Your structs are almost larger than they are worth. Link lists are pretty strait-foward already. They don't really need an extra layer simply for the act of deletion. You idea is a good one, but about 75% of the time it will be a little much.

[rafdggsfs]

Thanks mate.
I have thought of using linked lists but I just mastered dynamic arrays in my last project and I'm sure you know how it is: You always use the solution you found in your last project in your next project!

Anyway thanks for your help.

P.S The project is a simple and portable DNS resolver and once I put the finishing touches to it I hope to post it somewhere.