Function moq_error 

#[unsafe(no_mangle)]
pub extern "C" fn moq_error() -> *const c_char

Human-readable reason for the most recent failed call on the calling thread.

libmoq functions return only a negative code; this exposes the matching message (including detail the code can’t carry, e.g. which URL failed to parse or why a decode failed). The string is only meaningful after a call returned a negative code; check the code first.

Returns a NUL-terminated, UTF-8 pointer valid until the next libmoq call on the same thread, or NULL if no error has been recorded on this thread. Copy it if you need it to outlive the next call. Errors delivered through status callbacks carry their code directly; read this from inside the callback to get their reason.