Function version_check::supports_feature [−][src]
Expand description
Checks whether the running or installed rustc
supports feature
.
Returns true iff is_feature_flaggable()
returns true
and the
feature is not disabled via exclusion in allow-features
via RUSTFLAGS
or
CARGO_ENCODED_RUSTFLAGS
. If the version could not be determined, returns
None
.
Example
use version_check as rustc;
if let Some(true) = rustc::supports_feature("doc_cfg") {
println!("cargo:rustc-cfg=has_doc_cfg");
}