How to work with pointer to pointer to structure in C?

Hi, I want to change member of structure under double pointer. Do you know how?

Example code

typedef struct {
    int member;
} Ttype;

void changeMember(Ttype **foo) {
   //I don`t know how to do it
   //maybe
   *foo->member = 1;
}

Thanks for any help.

From stackoverflow

• maybe (*foo)->member = 1 (if it's dynamically allocated)

  Jonathan Leffler : No maybe - but dynamic allocation is immaterial.

• Try

  (*foo)->member = 1;
  

  You need to explicitly use the * first. Otherwise it's an attempt to dereference member.

• Due to operator precedence, you need to put parentheses around this:

  (*foo)->member = 1;
  

• Thanks for quick answer. Of course (*foo)->member is correct. I tried something like *(foo->member), (foo.member) and other bad things...

  Thanks a lot.

• You can use a temp variable to improve readability. For example:

  Ttype *temp = *foo;
  temp->member = 1;
  

  If you have control of this and allowed to use C++, the better way is to use reference. For example:

  void changeMember(Ttype *&foo) {
     foo->member = 1;
  }