pub const EMPTY: i64 = -1;Expand description
Sentinel for “not yet assigned” — matches every one of the three ported
packages’ own #define EMPTY (-1) (confirmed identical across
KLU/Include/klu_internal.h:77, AMD/Include/amd_internal.h:71,93, and
implicitly in BTF/Include/btf.h’s BTF_ISFLIPPED/BTF_UNFLIP, which
treat -1 the same way).