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rhaj/_archive/rhai_engine/rhaibook/language/timestamps.md
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Timestamps
==========
{{#include ../links.md}}
Timestamps are provided by the [`BasicTimePackage`][built-in packages] (excluded when using a [raw `Engine`])
via the `timestamp` function.
Timestamps are not available under [`no_time`] or [`no_std`].
The Rust type of a timestamp is `std::time::Instant` ([`instant::Instant`] in [WASM] builds).
[`type_of()`] a timestamp returns `"timestamp"`.
Built-in Functions
------------------
The following methods (defined in the [`BasicTimePackage`][built-in packages] but excluded when
using a [raw `Engine`]) operate on timestamps.
| Function | Parameter(s) | Description |
| ----------------------------- | ----------------------------------------------------------- | --------------------------------------------------------------------- |
| `elapsed` method and property | _none_ | returns the number of seconds since the timestamp |
| `+` operator | number of seconds to add | returns a new timestamp with a specified number of seconds added |
| `+=` operator | number of seconds to add | adds a specified number of seconds to the timestamp |
| `-` operator | number of seconds to subtract | returns a new timestamp with a specified number of seconds subtracted |
| `-=` operator | number of seconds to subtract | subtracts a specified number of seconds from the timestamp |
| `-` operator | <ol><li>later timestamp</li><li>earlier timestamp</li></ol> | returns the number of seconds between the two timestamps |
The following methods are defined in the [`LanguageCorePackage`][built-in packages] but excluded
when using a [raw `Engine`].
| Function | Not available under | Parameter(s) | Description |
| -------- | :-----------------: | -------------------------- | ----------------------------------------------------------- |
| `sleep` | [`no_std`] | number of seconds to sleep | blocks the current thread for a specified number of seconds |
Examples
--------
```rust
let now = timestamp();
// Do some lengthy operation...
if now.elapsed > 30.0 {
print("takes too long (over 30 seconds)!")
}
```