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Added measure-elapsed-time example (#343)

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Added measure-elapsed-time example
This commit is contained in:
Alexandru Ene 2017-10-26 07:37:12 +01:00 committed by Michał Budzyński
parent de94b25d40
commit 57ad48c505
3 changed files with 37 additions and 0 deletions
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33
src/basics.md
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@ -25,6 +25,7 @@
| [Access a file randomly using a memory map][ex-random-file-access] | [![memmap-badge]][memmap] | [![cat-filesystem-badge]][cat-filesystem] |
| [Check number of logical cpu cores][ex-check-cpu-cores] | [![num_cpus-badge]][num_cpus] | [![cat-hardware-support-badge]][cat-hardware-support] |
| [Obtain backtrace of complex error scenarios][ex-error-chain-backtrace] | [![error-chain-badge]][error-chain] | [![cat-rust-patterns-badge]][cat-rust-patterns] |
| [Measure elapsed time][ex-measure-elapsed-time] | [![std-badge]][std] | [![cat-time-badge]][cat-time] |
[ex-std-read-lines]: #ex-std-read-lines
<a name="ex-std-read-lines"></a>
@ -1188,6 +1189,34 @@ Error level - description
Run the recipe with `RUST_BACKTRACE=1` to display a detailed [`backtrace`] associated with this error.
[ex-measure-elapsed-time]: #ex-measure-elapsed-time
<a name="ex-measure-elapsed-time"></a>
## Measure the elapsed time between two code sections
[![std-badge]][std] [![cat-time-badge]][cat-time]
Measures [`time::Instant::elapsed`] since [`time::Instant::now`].
Calling [`time::Instant::elapsed`] returns a [`time::Duration`] that we print at the end of the example.
This method will not mutate or reset the [`time::Instant`] object.
```rust
use std::time::{Duration, Instant};
# use std::thread;
#
# fn expensive_function() {
# thread::sleep(Duration::from_secs(1));
# }
fn main() {
let start = Instant::now();
expensive_function();
let duration = start.elapsed();
println!("Time elapsed in expensive_function() is: {:?}", duration);
}
```
{{#include links.md}}
<!-- API Reference -->
@ -1215,6 +1244,10 @@ Run the recipe with `RUST_BACKTRACE=1` to display a detailed [`backtrace`] assoc
[`MutexGuard`]: https://doc.rust-lang.org/std/sync/struct.MutexGuard.html
[`Normal`]: https://doc.rust-lang.org/rand/rand/distributions/normal/struct.Normal.html
[`num_cpus::get`]: https://docs.rs/num_cpus/*/num_cpus/fn.get.html
[`time::Instant::now`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.now
[`time::Duration`]: https://doc.rust-lang.org/std/time/struct.Duration.html
[`time::Instant`]:https://doc.rust-lang.org/std/time/struct.Instant.html
[`time::Instant::elapsed`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.elapsed
[`Output`]: https://doc.rust-lang.org/std/process/struct.Output.html
[`pbkdf2::derive`]: https://docs.rs/ring/*/ring/pbkdf2/fn.derive.html
[`pbkdf2::verify`]: https://docs.rs/ring/*/ring/pbkdf2/fn.verify.html

2
src/intro.md
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@ -43,6 +43,7 @@ community. It needs and welcomes help. For details see
| [Access a file randomly using a memory map][ex-random-file-access] | [![memmap-badge]][memmap] | [![cat-filesystem-badge]][cat-filesystem] |
| [Check number of logical cpu cores][ex-check-cpu-cores] | [![num_cpus-badge]][num_cpus] | [![cat-hardware-support-badge]][cat-hardware-support] |
| [Obtain backtrace of complex error scenarios][ex-error-chain-backtrace] | [![error-chain-badge]][error-chain] | [![cat-rust-patterns-badge]][cat-rust-patterns] |
| [Measure elapsed time][ex-measure-elapsed-time] | [![std-badge]][std] | [![cat-time-badge]][cat-time] |
## [Encoding](encoding.html)
@ -161,6 +162,7 @@ community. It needs and welcomes help. For details see
[ex-threadpool-walk]: concurrency.html#ex-threadpool-walk
[ex-dedup-filenames]: app.html#ex-dedup-filenames
[ex-error-chain-backtrace]: basics.html#ex-error-chain-backtrace
[ex-measure-elapsed-time]: basics.html#ex-measure-elapsed-time
[ex-extract-links-webpage]: net.html#ex-extract-links-webpage
[ex-extract-hashtags]: basics.html#ex-extract-hashtags
[ex-extract-mediawiki-links]: net.html#ex-extract-mediawiki-links

2
src/links.md
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@ -37,6 +37,8 @@ Keep lines sorted.
[cat-rendering]: https://crates.io/categories/rendering
[cat-rust-patterns-badge]: https://badge-cache.kominick.com/badge/rust_patterns--x.svg?style=social
[cat-rust-patterns]: https://crates.io/categories/rust-patterns
[cat-time-badge]: https://badge-cache.kominick.com/badge/time--x.svg?style=social
[cat-time]: https://crates.io/categories/date-and-time
[cat-science-badge]: https://badge-cache.kominick.com/badge/science--x.svg?style=social
[cat-science]: https://crates.io/categories/science
[cat-text-processing-badge]: https://badge-cache.kominick.com/badge/text_processing--x.svg?style=social