Need to allocate?

[Bladactania]

If I have a pointer to a struct and I call a function which returns a pointer to a struct that already has memory allocated to it, do I need to allocate the memory for the original variable? consider the follwoing pseudocode...

main function {
  structure pointer s_ptr;

  s_ptr = some_function()
}

structure pointer some_function {
  structure pointer s_ptr_temp;

  s_ptr_temp = malloc(yadda yadda);

  return s_ptr_temp;
}

is this ok?

[laserlight]

Yes, it is okay, but somewhere before dereferencing the pointer you should check that malloc() did not return a null pointer, and somewhere after using the pointer you should free().

[Meldreth]

you only need to allocate memory for an address once. then you can have as many pointers as you want pointing to the address.

[Bladactania]

what about this?

int main() {
  struct mystruct *ptr = malloc(sizeof(mystruct));
  struct mystruct * ptr2;

  ptr2 = ptr1;
}

[vart]

what about this?

What about it?

[laserlight]

As Meldreth just noted, "you can have as many pointers as you want pointing to the address".

[Snafuist]

...but you may only free() the corresponding memory exactly once.

Greets,
Philip

[matsp]

...but you may only free() the corresponding memory exactly once.

Greets,
Philip

And, don't use any of the other pointers after the memory has been freed!

--
Mats