Node:Heap Cell Type Information, Next:Accessing Cell Entries, Previous:Non-immediate objects, Up:Unpacking the SCM type
Heap cells contain a number of entries, each of which is either a scheme
object of type SCM or a raw C value of type scm_t_bits.
Which of the cell entries contain Scheme objects and which contain raw C
values is determined by the first entry of the cell, which holds the
cell type information.
| scm_t_bits SCM_CELL_TYPE (SCM x) | Macro |
| For a non-immediate Scheme object x, deliver the content of the first entry of the heap cell referenced by x. This value holds the information about the cell type. |
| void SCM_SET_CELL_TYPE (SCM x, scm_t_bits t) | Macro |
| For a non-immediate Scheme object x, write the value t into the first entry of the heap cell referenced by x. The value t must hold a valid cell type. |