Is there a problem with reading multiple elements from a pointer with fread?

Question

Here is the structure:

typedef struct {
    int nr_operations;
    int *operations_idxs;
} sensor;

I try to read from a FILE elements in operations_idxs.

I get segmentation fault using this code:

S[i].operations_idxs=(int*)malloc(S[i].nr_operations*sizeof(int));
fread(&S[i].operations_idxs, sizeof(int), S[i].operations_idxs, f);

But works well with this code, reading right data:

S[i].operations_idxs=(int*)malloc(S[i].nr_operations*sizeof(int));
for( j=0; j<S[i].nr_operations; j++) {
    fread(&S[i].operations_idxs[j], sizeof(int), 1, f);
}

Answer 1

Well, i didn't see that i used the address of the pointer S[i].operations_idxs as the first argument.

So i had to use this to work:

 S[i].operations_idxs=(int*)malloc(S[i].nr_operations*sizeof(int));
 fread(S[i].operations_idxs, sizeof(int), S[i].operations_idxs, f);