UDB_XL_CHUNK
p = UDB_XL_CHUNK(ret);
udb_xl_chunk_d* xlp = UDB_XL_CHUNK(xl);
udb_xl_chunk_d* np = UDB_XL_CHUNK(n);
udb_xl_chunk_d* xlp = UDB_XL_CHUNK(xl);
udb_xl_chunk_d* xlp = UDB_XL_CHUNK(xl);
avail = UDB_XL_CHUNK(c)->size - sizeof(udb_xl_chunk_d)
xlsz = UDB_XL_CHUNK(ch)->size;
udb_xl_chunk_d* cp = UDB_XL_CHUNK(c);
UDB_XL_CHUNK(at)->ptrlist = 0;
at += UDB_XL_CHUNK(at)->size;
uint64_t sz = ((exp == UDB_EXP_XL)?UDB_XL_CHUNK(at)->size: