Crate universal_time 

Cross-platform time primitives.

Provides Instant and SystemTime plus traits for injecting custom platform clocks through a global time context.

universal-time

Cross-platform time primitives for Rust that can run in any envuironment.

Why

universal-time gives you a single API for:

• Instant for monotonic elapsed-time measurements
• SystemTime for wall-clock timestamps
• Trait-based clock injection for platforms without built-in time access

Quick Start

use universal_time::{Instant, SystemTime, UNIX_EPOCH};

fn main() {
    let start = Instant::now();
    let now = SystemTime::now();
    let elapsed = start.elapsed();
    let since_epoch = now.duration_since(UNIX_EPOCH).unwrap_or_default();

    println!("elapsed = {:?}", elapsed);
    println!("since epoch = {:?}", since_epoch);
}

For more examples, check out the examples directory.

Panic Behavior

In no_std mode, and in std mode on wasm32-unknown-unknown, both Instant::now() and SystemTime::now() panic when:

• no global context has been installed, or
• installed context returns None for that clock type

This is intentional so missing time sources fail fast instead of silently returning fake timestamps.

Concurrency Notes

• std: global context uses OnceLock
• no_std with atomics: global context uses lock-free once initialization
• no_std without atomics: fallback expects single-threaded startup initialization

Structs

Duration

A Duration type to represent a span of time, typically used for system timeouts.

GlobalTimeContextAlreadySet

Error returned when attempting to set the global time context more than once.

Instant

Monotonic clock reading.

SystemTime

Wall clock time represented as a duration since the Unix epoch.

Constants

UNIX_EPOCH

Unix epoch (January 1, 1970).

Traits

MonotonicClock

Source of monotonic instants.

TimeContext

A full time context that can provide wall-clock and monotonic time.

WallClock

Source of wall-clock timestamps.

Functions

global_time_context

Returns the globally configured time context if one was installed.

set_global_time_context

Installs the global time context.