Opaque Pointer Pattern

Declare struct in header without defining fields. Implementation hidden in .c file. Callers only see pointer, never fields.

ikigai Application

Header:

typedef struct ik_scrollback ik_scrollback_t;  // Forward declaration
res_t ik_scrollback_create(void *ctx, ik_scrollback_t **out);

Implementation in .c:

struct ik_scrollback {
    // Fields hidden from callers
};

Benefits:

• Callers can't depend on internal fields
• Change internals without recompiling callers
• Enforces use of accessor functions

ikigai usage: Most context types could use this. Currently structs are defined in headers. Consider for stable public APIs.