pub const DOMAIN_ID_EXPLICIT_ZERO_C_ABI: u8 = 255;Expand description
Issue #227 — C/C++-ABI escape for an EXPLICIT domain 0.
The C/C++ init surface carries domain_id as a u8 where 0 is the
UNSET sentinel (the #206 model-A / ROS-convention decision: unset defers
to env > baked macro > default). That makes a literal domain 0
unreachable once an image bakes a nonzero NROS_ENTRY_DOMAIN_ID. Since
valid domains cap at DOMAIN_ID_MAX (232), the value 255 is free:
passing it means “explicitly domain 0 — do NOT treat as unset”. Hosted
env still overrides it (model A), like every other explicit argument.