Get element from struct array

Returns a pointer to the i-th struct in a contiguous array of structs. The returned pointer shares memory with the original array.

Usage

ffi_get_element(ptr, index, struct_type)

Arguments

ptr

External pointer to struct array (from ffi_alloc with n > 1)

index

1-based index of element to get

struct_type

StructType describing the element type

Value

External pointer to the element (no finalizer - parent owns memory)

Examples

if (FALSE) { # \dontrun{
Point <- ffi_struct(x = ffi_int(), y = ffi_int())
points <- ffi_alloc(Point, 10L) # array of 10 Points
p3 <- ffi_get_element(points, 3L, Point)
ffi_set_field(p3, "x", 100L, Point)
} # }