dlsymfunc ()

void *
(*dlsymfunc) (void *handle,
              const char *symbol);

dlopnfunc ()

void *
(*dlopnfunc) (const char *file,
              int flags);

freefunc ()

void
(*freefunc) (void *ptr);

mallocfunc ()

void *
(*mallocfunc) (size_t size);

callocfunc ()

void *
(*callocfunc) (size_t nmem,
               size_t size);

rallocfunc ()

void *
(*rallocfunc) (void *ptr,
               size_t size);

palignfunc ()

int
(*palignfunc) (void **memptr,
               size_t alignment,
               size_t size);

struct capsule

struct capsule {
    void  *dl_handle;
    struct { ptr_list *all; ptr_list *some; } seen;
    capsule_metadata *meta;
    capsule_namespace *ns;
    capsule_item internal_wrappers[7];
};

A handle returned by capsule_init: A required parameter for all other capsule calls.