extern void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb,
size_t offset, int c, size_t len,
ssize_t pagecpy);
extern void _lib_ring_buffer_memset(struct lib_ring_buffer_backend *bufb,
size_t offset, int c, size_t len,
ssize_t pagecpy);
size_t offset, const void *src,
size_t len, ssize_t pagecpy);
size_t offset, const void *src,
size_t len, ssize_t pagecpy);