How can I assign a pointer to an array in c? As in this example, I want to some.x has values stored in vals
typedef struct s
{
int x[];
}s;
int main()
{
int* vals = malloc(sizeof(int) * 10);
for (int i = 0; i < 10; i++)
vals[i] = i + 10;
s some;
//some.x = vals?
return 0;
}
Assuming you want to allocate a structure with a flexible array member, and not assign a pointer to an array (which as others have stated - you can't do that)
To use a flexible array member, you need to allocate the structure plus an amount of memory for the array.
typedef struct s
{
int x[];
}s;
int main()
{
s *some = malloc( sizeof( *some ) + ( 10 * sizeof( int ) ) );
for ( int i = 0; i < 10; i++ )
some->x[i] = i + 10;
return 0;
}
Note that you can not leave the sizeof( struct ... ) out of the allocation - the structure's presence is not guaranteed to be zero, even when the flexible array member is the only field in the structure.
As @chux noted in the comments, this would be more consistent with using variables instead of types as sizeof() arguments:
s *some = malloc( sizeof( *some ) + ( 10 * sizeof( some->x[0] ) ) );
sizeof(variable) vs. sizeof (type), could use malloc( sizeof *some + 10*sizeof some->x[0] );Arrays are not pointers, thats all.
You cannot do what you want. It is outside of the C11 standard n1570.
Arrays do decay into pointers, but not the other way round. You cannot assign to an array.
So use systematically pointers.
And your code cannot have any sense: think of the sizeof involved data!
Read about flexible array members. You'll use pointers to a struct containing them.
_SCATTER_GATHER_LIST structure from MSDN: learn.microsoft.com/en-us/windows-hardware/drivers/ddi/content/… and I don't know how to assign elements to SCATTER_GATHER_ELEMENT Elements[]; field