Function current_os_id

pub(crate) fn current_os_id() -> u64

Gets the OS thread ID of the thread that invokes it, if available. If not, return the Rust thread ID.

We use a u64 to all possible platform IDs without excess cfg; most use int, some use a pointer, and Apple uses uint64_t. This is a “best effort” approach for diagnostics and is allowed to fall back to a non-OS ID (such as the Rust thread ID) or a non-unique ID (such as a PID) if the thread ID cannot be retrieved.