[][src]Crate built

Provides a crate with information from the time it was built.

built is used as a build-time dependency to collect various information about the build environment, serialize it into Rust-code and compile it into the final crate. The information collected by built include:

  • Various metadata like version, authors, homepage etc. as set by Cargo.toml
  • The tag or commit id if the crate was being compiled from within a git repo.
  • The values of various cfg!, like target_os and target_arch.
  • The features the crate was compiled with.
  • The various dependencies, dependencies of dependencies and their versions cargo ultimately chose to compile.
  • The presence of a CI-platform like Travis CI and AppVeyor.
  • The used compiler and it's version; the used documentation generator and it's version.

See the Options-type regarding what built can serialize.

built does not add any further dependencies to a crate; all information is serialized as types from stdlib. One can include built as a runtime-dependency and use it's convenience functions.

To add built to a crate, add it as a build-time dependency, use a build script that collects and serializes the build-time information and include! that as code.

Add this to Cargo.toml:

build = "build.rs"

built = "0.4"

Add or modify a build script. In build.rs:

fn main() {
    built::write_built_file().expect("Failed to acquire build-time information");

The build-script will by default write a file named built.rs into Cargo's output directory. It can be picked up in main.rs (or anywhere else) like this:

This example is not tested
// Use of a mod or pub mod is not actually necessary.
pub mod built_info {
   // The file has been placed there by the build script.
   include!(concat!(env!("OUT_DIR"), "/built.rs"));

And then used somewhere in the crate's code:

/// Determine if current version is a pre-release or was built from a git-repo
fn release_is_unstable() -> bool {
    return !built_info::PKG_VERSION_PRE.is_empty() || built_info::GIT_VERSION.is_some()

/// Default log-level, enhanced on CI
fn default_log_level() -> LogLevel {
    if built_info::CI_PLATFORM.is_some() {
    } else {

/// If another crate pulls in a dependency we don't like, print a warning
#[cfg(feature = "semver")]
fn check_sane_dependencies() {
    if built::util::parse_versions(&built_info::DEPENDENCIES)
                    .any(|(name, ver)| name == "DeleteAllMyFiles"
                                       && ver < semver::Version::parse("1.1.4").unwrap()) {
        eprintln!("DeleteAllMyFiles < 1.1.4 may not delete all your files. Beware!");

A full built.rs will look something like:

/// The Continuous Integration platform detected during compilation.
pub const CI_PLATFORM: Option<&str> = None;
#[doc="The full version."]
pub const PKG_VERSION: &str = "0.1.0";
#[doc="The major version."]
pub const PKG_VERSION_MAJOR: &str = "0";
#[doc="The minor version."]
pub const PKG_VERSION_MINOR: &str = "1";
#[doc="The patch version."]
pub const PKG_VERSION_PATCH: &str = "0";
#[doc="The pre-release version."]
pub const PKG_VERSION_PRE: &str = "";
#[doc="A colon-separated list of authors."]
pub const PKG_AUTHORS: &str = "Lukas Lueg <lukas.lueg@gmail.com>";
#[doc="The name of the package."]
pub const PKG_NAME: &str = "example_project";
#[doc="The description."]
pub const PKG_DESCRIPTION: &str = "";
#[doc="The homepage."]
pub const PKG_HOMEPAGE: &str = "";
#[doc="The license."]
pub const PKG_LICENSE: &str = "MIT";
#[doc="The source repository as advertised in Cargo.toml."]
pub const PKG_REPOSITORY: &str = "";
#[doc="The target triple that was being compiled for."]
pub const TARGET: &str = "x86_64-unknown-linux-gnu";
#[doc="The host triple of the rust compiler."]
pub const HOST: &str = "x86_64-unknown-linux-gnu";
#[doc="`release` for release builds, `debug` for other builds."]
pub const PROFILE: &str = "debug";
#[doc="The compiler that cargo resolved to use."]
pub const RUSTC: &str = "rustc";
#[doc="The documentation generator that cargo resolved to use."]
pub const RUSTDOC: &str = "rustdoc";
#[doc="Value of OPT_LEVEL for the profile used during compilation."]
pub const OPT_LEVEL: &str = "0";
#[doc="The parallelism that was specified during compilation."]
pub const NUM_JOBS: u32 = 8;
#[doc="Value of DEBUG for the profile used during compilation."]
pub const DEBUG: bool = true;
/// The features that were enabled during compilation.
pub const FEATURES: [&str; 0] = [];
/// The features as a comma-separated string.
pub const FEATURES_STR: &str = "";
/// The output of `rustc -V`
pub const RUSTC_VERSION: &str = "rustc 1.43.1 (8d69840ab 2020-05-04)";
/// The output of `rustdoc -V`
pub const RUSTDOC_VERSION: &str = "rustdoc 1.43.1 (8d69840ab 2020-05-04)";
/// If the crate was compiled from within a git-repository, `GIT_VERSION` contains HEAD's tag. The short commit id is used if HEAD is not tagged.
pub const GIT_VERSION: Option<&str> = Some("0.4.1-10-gca2af4f");
/// If the repository had dirty/staged files.
pub const GIT_DIRTY: Option<bool> = Some(true);
/// If the crate was compiled from within a git-repository, `GIT_HEAD_REF` contains full name to the reference pointed to by HEAD (e.g.: `refs/heads/master`). If HEAD is detached or the branch name is not valid UTF-8 `None` will be stored.
pub const GIT_HEAD_REF: Option<&str> = Some("refs/heads/master");
/// If the crate was compiled from within a git-repository, `GIT_COMMIT_HASH` contains HEAD's full commit SHA-1 hash.
pub const GIT_COMMIT_HASH: Option<&str> = Some("ca2af4f11bb8f4f6421c4cccf428bf4862573daf");
/// An array of effective dependencies as documented by `Cargo.lock`.
pub const DEPENDENCIES: [(&str, &str); 39] = [("autocfg", "1.0.0"), ("bitflags", "1.2.1"), ("built", "0.4.1"), ("cargo-lock", "4.0.1"), ("cc", "1.0.54"), ("cfg-if", "0.1.10"), ("chrono", "0.4.11"), ("example_project", "0.1.0"), ("git2", "0.13.6"), ("idna", "0.2.0"), ("jobserver", "0.1.21"), ("libc", "0.2.71"), ("libgit2-sys", "0.12.6+1.0.0"), ("libz-sys", "1.0.25"), ("log", "0.4.8"), ("matches", "0.1.8"), ("num-integer", "0.1.42"), ("num-traits", "0.2.11"), ("percent-encoding", "2.1.0"), ("pkg-config", "0.3.17"), ("proc-macro2", "1.0.17"), ("quote", "1.0.6"), ("semver", "0.10.0"), ("semver", "0.9.0"), ("semver-parser", "0.7.0"), ("serde", "1.0.110"), ("serde_derive", "1.0.110"), ("smallvec", "1.4.0"), ("syn", "1.0.25"), ("time", "0.1.43"), ("toml", "0.5.6"), ("unicode-bidi", "0.3.4"), ("unicode-normalization", "0.1.12"), ("unicode-xid", "0.2.0"), ("url", "2.1.1"), ("vcpkg", "0.2.8"), ("winapi", "0.3.8"), ("winapi-i686-pc-windows-gnu", "0.4.0"), ("winapi-x86_64-pc-windows-gnu", "0.4.0")];
/// The effective dependencies as a comma-separated string.
pub const DEPENDENCIES_STR: &str = "autocfg 1.0.0, bitflags 1.2.1, built 0.4.1, cargo-lock 4.0.1, cc 1.0.54, cfg-if 0.1.10, chrono 0.4.11, example_project 0.1.0, git2 0.13.6, idna 0.2.0, jobserver 0.1.21, libc 0.2.71, libgit2-sys 0.12.6+1.0.0, libz-sys 1.0.25, log 0.4.8, matches 0.1.8, num-integer 0.1.42, num-traits 0.2.11, percent-encoding 2.1.0, pkg-config 0.3.17, proc-macro2 1.0.17, quote 1.0.6, semver 0.10.0, semver 0.9.0, semver-parser 0.7.0, serde 1.0.110, serde_derive 1.0.110, smallvec 1.4.0, syn 1.0.25, time 0.1.43, toml 0.5.6, unicode-bidi 0.3.4, unicode-normalization 0.1.12, unicode-xid 0.2.0, url 2.1.1, vcpkg 0.2.8, winapi 0.3.8, winapi-i686-pc-windows-gnu 0.4.0, winapi-x86_64-pc-windows-gnu 0.4.0";
/// The built-time in RFC2822, UTC
pub const BUILT_TIME_UTC: &str = "Wed, 27 May 2020 18:12:39 +0000";
/// The target architecture, given by `cfg!(target_arch)`.
pub const CFG_TARGET_ARCH: &str = "x86_64";
/// The endianness, given by `cfg!(target_endian)`.
pub const CFG_ENDIAN: &str = "little";
/// The toolchain-environment, given by `cfg!(target_env)`.
pub const CFG_ENV: &str = "gnu";
/// The OS-family, given by `cfg!(target_family)`.
pub const CFG_FAMILY: &str = "unix";
/// The operating system, given by `cfg!(target_os)`.
pub const CFG_OS: &str = "linux";
/// The pointer width, given by `cfg!(target_pointer_width)`.
pub const CFG_POINTER_WIDTH: &str = "64";



Various convenience functions for built at runtime.



Selects which information built should retrieve and write as Rust code. Used in conjunction with write_built_file_with_opts.



Various Continuous Integration platforms whose presence can be detected.



A shorthand for calling write_built_file() with CARGO_MANIFEST_DIR and [OUT_DIR]/built.rs.


Writes rust-code describing the crate at manifest_location to a new file named dst.