I dont understand what is a pointer to a pointer if p is a pointer to a structure ( struct str* p

Question

so p contain the adress of the structure using malloc but what does *p contain ??
what is the meaning of struct str **p; ??

Answer 1

struct str v, *p, **p;
p = &v;
pp = &p;

Here we have those relations :
*p ==**pp == v
pp == &p == &&v
p == *pp == &v

Answer 2

Simple
* Means VALUE AT
&Means ADDRESS OF

*P means the value which is stored in the variable.

&P means the address of that variable.

I think you got the answer