Array assignment with struct pointers in C

Question

I need to hold a dynamic array of structs.

The types are defined like this. I'm not able to change those, because they are given by a library called flint (library for fast number theory).

typedef struct
{
 mp_ptr coeffs;
 slong alloc;
 slong length;
 nmod_t mod;
} nmod_poly_struct;
typedef nmod_poly_struct nmod_poly_t[1];

and my struct is defined like this:

typedef struct {
 mp_limb_t D;
 mp_limb_t length;
 nmod_poly_t *s;
} she_key_symmetric_t;

So my problem is to hold a set of nmod_poly_t objects. I initialize them and want so store them in the array.

nmod_poly_t poly;
nmod_poly_init(poly);
she_key_symmetric_t key;
// init and stuff
key.s[0] = poly; // This line does not work, because 
// it always says "array type 'nmod_poly_t' (aka 
// 'nmod_poly_struct[1]') is not assignable"

In the next step I have to get the values back out of the array

she_key_symmetric_t key;
// fully initialized key
nmod_poly_t poly = key.s[0]; 

So how do I need to declare my dynamic array s to store my strucs inside it?

Thanks in advance

• Edward: Are you wanting a solution in C or C++? The answers may be very different depending on which you choose.
• Arndt Bieberstein: nmod_poly_t poly = key.s[0]; => nmod_poly_t poly; poly[0] =key.s[0][0]; actually works. Plain C is preferred.
• Mats Petersson: Removing C++ tag, since it seems like C++ isn't really the language being asked about.

Answer 1

Following will work, assuming memory allocated properly for key.s and initialized

nmod_poly_t poly; 
poly[0] =key.s[0][0];