Function pio_contingency_resolution_case_unresolved_reason 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn pio_contingency_resolution_case_unresolved_reason(
    resolution: *const PioContingencyResolution,
    case_index: usize,
    unresolved_index: usize,
    error: *mut *mut PioError,
) -> PioStringView

Read why one action of one case bound to nothing, as a fixed snake case name: no_such_bus, no_such_branch, ambiguous_branch, ambiguous_transformer_3w, no_such_machine, no_such_shunt, no_such_load, no_such_transformer_3w, or unrecognized. Python reports the same names.

Safety

Pointers and handles must satisfy the crate-level safety requirements.