| channel.rs |
|
5425 |
| date.rs |
|
6198 |
| lib.rs |
This tiny crate checks that the running or installed `rustc` meets some
version requirements. The version is queried by calling the Rust compiler
with `--version`. The path to the compiler is determined first via the
`RUSTC` environment variable. If it is not set, then `rustc` is used. If
that fails, no determination is made, and calls return `None`.
# Examples
* Set a `cfg` flag in `build.rs` if the running compiler was determined to
be at least version `1.13.0`:
```rust
extern crate version_check as rustc;
if rustc::is_min_version("1.13.0").unwrap_or(false) {
println!("cargo:rustc-cfg=question_mark_operator");
}
```
See [`is_max_version`] or [`is_exact_version`] to check if the compiler
is _at most_ or _exactly_ a certain version.
* Check that the running compiler was released on or after `2018-12-18`:
```rust
extern crate version_check as rustc;
match rustc::is_min_date("2018-12-18") {
Some(true) => "Yep! It's recent!",
Some(false) => "No, it's older.",
None => "Couldn't determine the rustc version."
};
```
See [`is_max_date`] or [`is_exact_date`] to check if the compiler was
released _prior to_ or _exactly on_ a certain date.
* Check that the running compiler supports feature flags:
```rust
extern crate version_check as rustc;
match rustc::is_feature_flaggable() {
Some(true) => "Yes! It's a dev or nightly release!",
Some(false) => "No, it's stable or beta.",
None => "Couldn't determine the rustc version."
};
```
* Check that the running compiler supports a specific feature:
```rust
extern crate version_check as rustc;
if let Some(true) = rustc::supports_feature("doc_cfg") {
println!("cargo:rustc-cfg=has_doc_cfg");
}
```
* Check that the running compiler is on the stable channel:
```rust
extern crate version_check as rustc;
match rustc::Channel::read() {
Some(c) if c.is_stable() => format!("Yes! It's stable."),
Some(c) => format!("No, the channel {} is not stable.", c),
None => format!("Couldn't determine the rustc version.")
};
```
To interact with the version, release date, and release channel as structs,
use [`Version`], [`Date`], and [`Channel`], respectively. The [`triple()`]
function returns all three values efficiently.
# Alternatives
This crate is dead simple with no dependencies. If you need something more
and don't care about panicking if the version cannot be obtained, or if you
don't mind adding dependencies, see
[rustc_version](https://crates.io/crates/rustc_version). |
19153 |
| version.rs |
|
10435 |