the Stopwatch wasn't compiling with cargo
cargo 0.2.0-nightly (efb482d 2015-04-30) (built 2015-04-29)

src/lib.rs:9:5: 9:26 error: unresolved import std::num::ToPrimitive. There is no ToPrimitive in std::num
src/lib.rs:9 use std::num::ToPrimitive;
^~~~~~~~~~~~~~~~~~~~~
error: aborting due to previous error
Could not compile stopwatch.

• start_new() is presumably a convenience method for doing new() + start() in one call?
• Difference between reset() and restart()?

Just from a glance of the the minimal info presented to a user, those were two things that stood out. Compared to using the standard Instant from Rust, I was interested in time taken between calls, turned out that was added as a feature that never arrived to crates.io.

As a user, I can try the methods out individually, but knowing in advance would have been nicer. Below is for any other user not wanting to try the API out or look over source:

• restart(): Continues running the timer but restarting from 0.
• reset(): Stops the timer and resets the value to 0.
• stop(): Stops the timer but doesn't reset the value.
• new(): Creates a timer but does not start it. restart() will also initiate the timer like start(). Must be mutable to track time.
• start_new(): Creates the timer and starts it. Does not need to be mutable for elapsed time tracking.

For lap functionality where you want to get the elapsed time since your previous measurement, you need a mutable stopwatch and to call sw.restart() between your two sw.elapsed_ms() calls. Alternatively if you source the crate from github instead of crates.io, you can use sw.elapsed_split_ms()

I have added this as a dependency to my Cargo-file like this:

[dependencies]
stopwatch = "0.0.3"

Trying to do a cargo build results in the following error:

    Updating registry `https://github.com/rust-lang/crates.io-index`
 Downloading gcc v0.1.5
 Downloading time v0.1.12
 Downloading stopwatch v0.0.3
   Compiling gcc v0.1.5
   Compiling time v0.1.12
   Compiling stopwatch v0.0.3
/home/nobbz/.cargo/registry/src/github.com-1ecc6299db9ec823/stopwatch-0.0.3/src/lib.rs:35:28: 35:36 error: type `u64` does not implement any method in scope named `to_i64`
/home/nobbz/.cargo/registry/src/github.com-1ecc6299db9ec823/stopwatch-0.0.3/src/lib.rs:35   let diff_i = match diff_u.to_i64() {
                                                                                                                          ^~~~~~~~
error: aborting due to previous error
Could not compile `stopwatch`.

edit
I use rust version rustc 1.0.0-nightly (170c4399e 2015-01-14 00:41:55 +0000)

It would be nice to have a utility function that tracks execution time of a given closure or function.

Useful crate but:

Using cargo 1.76.0 (c84b36747 2024-01-18) on fails compiling throwing:

error[E0310]: the parameter type `T` may not live long enough
    --> /home/user/.cargo/registry/src/index.crates.io-6f17d22bba15001f/rustc-serialize-0.3.24/src/serialize.rs:1155:5
     |
1155 |     fn decode<D: Decoder>(d: &mut D) -> Result<Cow<'static, T>, D::Error> {
     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |     |
     |     the parameter type `T` must be valid for the static lifetime...
     |     ...so that the type `T` will meet its required lifetime bounds...
     |
note: ...that is required by this bound
    --> /home/user/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/borrow.rs:180:30
     |
180  | pub enum Cow<'a, B: ?Sized + 'a>
     |                              ^^
help: consider adding an explicit lifetime bound
     |
1151 | impl<'a, T: ?Sized + 'static> Decodable for Cow<'a, T>
     |                    +++++++++

This issue was automatically generated. Feel free to close without ceremony if
you do not agree with re-licensing or if it is not possible for other reasons.
Respond to @cmr with any questions or concerns, or pop over to
#rust-offtopic on IRC to discuss.

You're receiving this because someone (perhaps the project maintainer)
published a crates.io package with the license as "MIT" xor "Apache-2.0" and
the repository field pointing here.

TL;DR the Rust ecosystem is largely Apache-2.0. Being available under that
license is good for interoperation. The MIT license as an add-on can be nice
for GPLv2 projects to use your code.

Why?

The MIT license requires reproducing countless copies of the same copyright
header with different names in the copyright field, for every MIT library in
use. The Apache license does not have this drawback. However, this is not the
primary motivation for me creating these issues. The Apache license also has
protections from patent trolls and an explicit contribution licensing clause.
However, the Apache license is incompatible with GPLv2. This is why Rust is
dual-licensed as MIT/Apache (the "primary" license being Apache, MIT only for
GPLv2 compat), and doing so would be wise for this project. This also makes
this crate suitable for inclusion and unrestricted sharing in the Rust
standard distribution and other projects using dual MIT/Apache, such as my
personal ulterior motive, the Robigalia project.

Some ask, "Does this really apply to binary redistributions? Does MIT really
require reproducing the whole thing?" I'm not a lawyer, and I can't give legal
advice, but some Google Android apps include open source attributions using
this interpretation. Others also agree with
it.
But, again, the copyright notice redistribution is not the primary motivation
for the dual-licensing. It's stronger protections to licensees and better
interoperation with the wider Rust ecosystem.

How?

To do this, get explicit approval from each contributor of copyrightable work
(as not all contributions qualify for copyright, due to not being a "creative
work", e.g. a typo fix) and then add the following to your README:

## License

Licensed under either of

 * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any
additional terms or conditions.

and in your license headers, if you have them, use the following boilerplate
(based on that used in Rust):

// Copyright 2016 rust-stopwatch developers
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

It's commonly asked whether license headers are required. I'm not comfortable
making an official recommendation either way, but the Apache license
recommends it in their appendix on how to use the license.

Be sure to add the relevant LICENSE-{MIT,APACHE} files. You can copy these
from the Rust repo for a plain-text
version.

And don't forget to update the license metadata in your Cargo.toml to:

license = "MIT/Apache-2.0"

I'll be going through projects which agree to be relicensed and have approval
by the necessary contributors and doing this changes, so feel free to leave
the heavy lifting to me!

Contributor checkoff

To agree to relicensing, comment with :

I license past and future contributions under the dual MIT/Apache-2.0 license, allowing licensees to chose either at their option.

Or, if you're a contributor, you can check the box in this repo next to your
name. My scripts will pick this exact phrase up and check your checkbox, but
I'll come through and manually review this issue later as well.

• @ellisonch
• @justinlatimer
• @AaronJRubin

HI!

As far as I know issue #5 is already done, but since I'm getting the same error message when I'm using dependency "*" in my Cargo.toml I think there needs to be a new versio uploaded (?)
I'm getting version 0.5 which seems too old. I'm expecting 0.6
Can you please publish a new build?

Please ;)

It woud be nice to have lap timing functionality.