CARGO-BUILD(1)

📦 version 1.93.1, in ubuntu resolute

💖 CARGO-BUILD(1) 💖

okay so bestie, this is the manual page for cargo-build — aka the command that turns your cute little source files into actual compiled artifacts. it's giving ✨*the*✨ build command. let's get into it, no cap.

🌸 NAME 🌸

cargo-build — Compile the current package 💅

🦋 SYNOPSIS 🦋

cargo build [options]

that's it. that's the whole vibe. options go brrr, package gets built.

🎀 DESCRIPTION 🎀

Compile local packages and all of their dependencies. 🫶

yes bestie, all of them. the whole dependency tree gets pulled in. it's a whole thing. iconic behavior honestly.

✨ OPTIONS ✨

👑 Package Selection

okay so here's the tea on how Cargo picks what to build when you don't say anything: by default, when no package selection options are given, the packages selected depend on the selected manifest file (based on the current working directory if --manifest-path is not given). If the manifest is the root of a workspace then the workspace's default members are selected, otherwise only the package defined by the manifest will be selected.

The default members of a workspace can be set explicitly with the workspace.default-members key in the root manifest. If this is not set, a virtual workspace will include all workspace members (equivalent to passing --workspace), and a non-virtual workspace will include only the root crate itself. 💀 that's a real difference bestie, don't sleep on it.

  • -p spec…, --package spec… — Build only the specified packages. Peep cargo-pkgid(1) for the SPEC format. This flag may be specified multiple times and supports common Unix glob patterns like *, ? and []. However — and this is the part that gets people 😭 — to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each pattern.
  • --workspace — Build all members in the workspace. the whole squad. 🫂
  • --all — Deprecated alias for --workspace. it's giving 2016. still works tho.
  • --exclude *SPEC*… — Exclude the specified packages. Must be used in conjunction with the --workspace flag. This flag may be specified multiple times and supports common Unix glob patterns like *, ? and []. However, to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each pattern. (same quote drama as above, fr fr)

🎯 Target Selection

When no target selection options are given, cargo build will build all binary and library targets of the selected packages. Binaries are skipped if they have required-features that are missing. 🙈

Binary targets are automatically built if there is an integration test or benchmark being selected to build. This allows an integration test to execute the binary to exercise and test its behavior. The CARGO_BIN_EXE_<name> environment variable (<https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-crates>) is set when the integration test is built so that it can use the env macro (<https://doc.rust-lang.org/std/macro.env.html>) to locate the executable. lowkey genius tbh.

Passing target selection flags will build only the specified targets. so if you pick one, you're picking one. periodt.

⚠️ heads up bestie: note that --bin, --example, --test and --bench flags also support common Unix glob patterns like *, ? and []. However, to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each glob pattern.
  • --lib — Build the package's library. 📚
  • --bin *name*… — Build the specified binary. This flag may be specified multiple times and supports common Unix glob patterns.
  • --bins — Build all binary targets.
  • --example *name*… — Build the specified example. This flag may be specified multiple times and supports common Unix glob patterns.
  • --examples — Build all example targets.
  • --test *name*… — Build the specified integration test. This flag may be specified multiple times and supports common Unix glob patterns.
  • --tests — Build all targets that have the test = true manifest flag set. By default this includes the library and binaries built as unittests, and integration tests. Be aware that this will also build any required dependencies, so the lib target may be built twice (once as a unittest, and once as a dependency for binaries, integration tests, etc.). Targets may be enabled or disabled by setting the test flag in the manifest settings for the target. 🔁 yes, twice. that's not a typo, that's just how it is.
  • --bench *name*… — Build the specified benchmark. This flag may be specified multiple times and supports common Unix glob patterns.
  • --benches — Build all targets that have the bench = true manifest flag set. By default this includes the library and binaries built as benchmarks, and bench targets. Be aware that this will also build any required dependencies, so the lib target may be built twice (once as a benchmark, and once as a dependency for binaries, benchmarks, etc.). Targets may be enabled or disabled by setting the bench flag in the manifest settings for the target.
  • --all-targets — Build all targets. This is equivalent to specifying --lib --bins --tests --benches --examples. the "do everything" button. 💅

🌈 Feature Selection

The feature flags allow you to control which features are enabled. When no feature options are given, the default feature is activated for every selected package. 🎀

See the features documentation (<https://doc.rust-lang.org/cargo/reference/features.html#command-line-feature-options>) for more details.

  • -F features, --features features — Space or comma separated list of features to activate. Features of workspace members may be enabled with package-name/feature-name syntax. This flag may be specified multiple times, which enables all specified features. 🫶
  • --all-features — Activate all available features of all selected packages. literally all of them. go off.
  • --no-default-features — Do not activate the default feature of the selected packages. bye default, you're not invited 🙈

🔥 Compilation Options

  • --target triple — Build for the specified target architecture. Flag may be specified multiple times. The default is the host architecture. The general format of the triple is <arch><sub>-<vendor>-<sys>-<abi>.

Possible values:

  • Any supported target in rustc --print target-list.
  • "host-tuple", which will internally be substituted by the host's target. This can be particularly useful if you're cross-compiling some crates, and don't want to specify your host's machine as a target (for instance, an xtask in a shared project that may be worked on by many hosts). 👑
  • A path to a custom target specification. See Custom Target Lookup Path (<https://doc.rust-lang.org/rustc/targets/custom.html#custom-target-lookup-path>) for more information.

This may also be specified with the build.target config value (<https://doc.rust-lang.org/cargo/reference/config.html>).

⚠️ Note that specifying this flag makes Cargo run in a different mode where the target artifacts are placed in a separate directory. See the build cache (<https://doc.rust-lang.org/cargo/reference/build-cache.html>) documentation for more details. so like… your stuff goes somewhere else. don't panic when you can't find it. 😭
  • -r, --release — Build optimized artifacts with the release profile. See also the --profile option for choosing a specific profile by name. optimized, fast, slay. 🏎️
  • --profile name — Build with the given profile. See the reference (<https://doc.rust-lang.org/cargo/reference/profiles.html>) for more details on profiles.
  • --timings=fmts — Output information how long each compilation takes, and track concurrency information over time. Accepts an optional comma-separated list of output formats; --timings without an argument will default to --timings=html. Specifying an output format (rather than the default) is unstable and requires -Zunstable-options. Valid output formats:
    • html (unstable, requires -Zunstable-options): Write a human-readable file cargo-timing.html to the target/cargo-timings directory with a report of the compilation. Also write a report to the same directory with a timestamp in the filename if you want to look at older runs. HTML output is suitable for human consumption only, and does not provide machine-readable timing data.
    • json (unstable, requires -Zunstable-options): Emit machine-readable JSON information about timing information. for the robots. 🤖

🍓 Output Options

  • --target-dir directory — Directory for all generated artifacts and intermediate files. May also be specified with the CARGO_TARGET_DIR environment variable, or the build.target-dir config value (<https://doc.rust-lang.org/cargo/reference/config.html>). Defaults to target in the root of the workspace. that's the target/ folder you keep gitignoring bestie 💅
  • --artifact-dir directory — Copy final artifacts to this directory.
🚨 This option is unstable and available only on the nightly channel (<https://doc.rust-lang.org/book/appendix-07-nightly-rust.html>) and requires the -Z unstable-options flag to enable. See <https://github.com/rust-lang/cargo/issues/6790> for more information.

🧚 Display Options

  • -v, --verbose — Use verbose output. May be specified twice for "very verbose" output which includes extra output such as dependency warnings and build script output. May also be specified with the term.verbose config value (<https://doc.rust-lang.org/cargo/reference/config.html>). yes bestie, -vv is a real thing and it's a lot. 😭
  • -q, --quiet — Do not print cargo log messages. May also be specified with the term.quiet config value (<https://doc.rust-lang.org/cargo/reference/config.html>). silence. peace. 🧘
  • --color when — Control when colored output is used. Valid values:
    • auto (default): Automatically detect if color support is available on the terminal.
    • always: Always display colors. 🌈
    • never: Never display colors.

May also be specified with the term.color config value (<https://doc.rust-lang.org/cargo/reference/config.html>).

  • --message-format fmt — The output format for diagnostic messages. Can be specified multiple times and consists of comma-separated values. Valid values:
    • human (default): Display in a human-readable text format. Conflicts with short and json.
    • short: Emit shorter, human-readable text messages. Conflicts with human and json.
    • json: Emit JSON messages to stdout. See the reference (<https://doc.rust-lang.org/cargo/reference/external-tools.html#json-messages>) for more details. Conflicts with human and short.
    • json-diagnostic-short: Ensure the rendered field of JSON messages contains the "short" rendering from rustc. Cannot be used with human or short.
    • json-diagnostic-rendered-ansi: Ensure the rendered field of JSON messages contains embedded ANSI color codes for respecting rustc's default color scheme. Cannot be used with human or short.
  • json-render-diagnostics — okay so this one is a whole vibe. It tells Cargo to not include rustc diagnostics in the JSON messages printed, but instead Cargo itself should render the JSON diagnostics coming from rustc. Cargo’s own JSON diagnostics and others coming from rustc are still emitted. And bestie, you cannot use this with human or short. Periodt. 💅

📦 Manifest Options 📦

  • --manifest-path path — this is where you point Cargo to your Cargo.toml file. By default, Cargo is a little detective and searches for Cargo.toml in the current directory or any parent directory. But if you wanna be specific, pass the path here. No cap. 🔍
  • --ignore-rust-version — just ignore the rust-version specification in packages. Like, pretend it's not there. 🙈
  • --locked — okay so this one asserts that the exact same dependencies and versions are used as when the existing Cargo.lock file was originally generated. Cargo will exit with an error when either of the following scenarios arises:
    • The lock file is missing. 😱
    • Cargo attempted to change the lock file due to a different dependency resolution. 💀 It may be used in environments where deterministic builds are desired, such as in CI pipelines. So if you want your builds to be consistent, this is your bestie. 🔒
  • --offline — prevents Cargo from accessing the network for any reason. Without this flag, Cargo will stop with an error if it needs to access the network and the network is not available. With this flag, Cargo will attempt to proceed without the network if possible. But beware, bestie: this may result in different dependency resolution than online mode. Cargo will restrict itself to crates that are downloaded locally, even if there might be a newer version as indicated in the local copy of the index. See the cargo-fetch(1) command to download dependencies before going offline. May also be specified with the net.offline config value https://doc.rust-lang.org/cargo/reference/config.html. 📴
  • --frozen — this is equivalent to specifying both --locked and --offline. So it's like a combo meal. 🧊
  • --lockfile-path PATH — changes the path of the lockfile from the default (<workspace_root>/Cargo.lock) to PATH. PATH must end with Cargo.lock (e.g. --lockfile-path /tmp/temporary-lockfile/Cargo.lock). Note that providing --lockfile-path will ignore existing lockfile at the default path, and instead will either use the lockfile from PATH, or write a new lockfile into the provided PATH if it doesn’t exist. This flag can be used to run most commands in read-only directories, writing lockfile into the provided PATH. This option is only available on the nightly channel https://doc.rust-lang.org/book/appendix-07-nightly-rust.html and requires the -Z unstable-options flag to enable (see #14421 https://github.com/rust-lang/cargo/issues/14421). So yeah, nightly only, bestie. 🌙

✨ Common Options ✨

  • +toolchain — if Cargo has been installed with rustup, and the first argument to cargo begins with +, it will be interpreted as a rustup toolchain name (such as +stable or +nightly). See the rustup documentation https://rust-lang.github.io/rustup/overrides.html for more information about how toolchain overrides work. So you can switch toolchains on the fly. Slay. 🦀
  • --config KEY=VALUE or PATH — overrides a Cargo configuration value. The argument should be in TOML syntax of KEY=VALUE, or provided as a path to an extra configuration file. This flag may be specified multiple times. See the command-line overrides section https://doc.rust-lang.org/cargo/reference/config.html#command-line-overrides for more information. So you can tweak configs from the command line. Iconic. ⚙️
  • -C PATH — changes the current working directory before executing any specified operations. This affects things like where cargo looks by default for the project manifest (Cargo.toml), as well as the directories searched for discovering .cargo/config.toml, for example. This option must appear before the command name, for example cargo -C path/to/my-project build. This option is only available on the nightly channel https://doc.rust-lang.org/book/appendix-07-nightly-rust.html and requires the -Z unstable-options flag to enable (see #10098 https://github.com/rust-lang/cargo/issues/10098). So it's like cd but for Cargo. Nightly only though. 🌙
  • -h, --help — prints help information. The classic. 🙌
  • -Z flag — unstable (nightly-only) flags to Cargo. Run cargo -Z help for details. So if you're feeling adventurous, this is your portal. 🌀

🎀 Miscellaneous Options 🎀

  • -j N, --jobs N — number of parallel jobs to run. May also be specified with the build.jobs config value https://doc.rust-lang.org/cargo/reference/config.html. Defaults to the number of logical CPUs. If negative, it sets the maximum number of parallel jobs to the number of logical CPUs plus provided value. If a string default is provided, it sets the value back to defaults. Should not be 0. So don't be a zero, bestie. 💅
  • --keep-going — build as many crates in the dependency graph as possible, rather than aborting the build on the first one that fails to build. For example if the current package depends on dependencies fails and works, one of which fails to build, cargo build -j1 may or may not build the one that succeeds (depending on which one of the two builds Cargo picked to run first), whereas cargo build -j1 --keep-going would definitely run both builds, even if the one run first fails. So it's like "keep going, bestie, you got this!" 💪
  • --future-incompat-report — displays a future-incompat report for any future-incompatible warnings produced during execution of this command. See cargo-report(1). So you can peek into the future of your code. 🔮

🌍 ENVIRONMENT 🌍

See the reference https://doc.rust-lang.org/cargo/reference/environment-variables.html for details on environment variables that Cargo reads. So many env vars, so little time. 🌈

🚦 EXIT STATUS 🚦

  • 0: Cargo succeeded. Yay! 🎉
  • 101: Cargo failed to complete. F in the chat. 😭

💡 EXAMPLES 💡

  1. Build the local package and all of its dependencies:
cargo build
  1. Build with optimizations:
cargo build --release

🔗 SEE ALSO 🔗

And that's a wrap on the CARGO-BUILD(1) manpage, bestie! This page is from the Cargo manual, and the footer just says CARGO-BUILD(1). Check your local Cargo version for the exact version and date. Stay slaying those builds! 💖✨

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