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

Question

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;
}

Answer 1

Try

(*foo)->member = 1;

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