CARGO-BUILD(1)

📦 version 1.81.0, in ubuntu jammy, ubuntu noble

💖 NAME 💖

cargo-build — bestie, this is the one that compiles your current package. It's giving "make it build" energy, and honestly? iconic.

🌸 SYNOPSIS 🌸

cargo build [options]

🎀 DESCRIPTION 🎀

It compiles local packages and all of their dependencies. That's it, that's the whole vibe. No cap, it just builds. 💅

✨ OPTIONS ✨

🫶 Package Selection

Okay so here's the tea, bestie: by default, when you give no package selection options, the packages that get selected depend on the selected manifest file (which is based on the current working directory if --manifest-path is not given). If that manifest is the root of a workspace, then the workspace's default members get selected. Otherwise? Only the package defined by the manifest. Simple as that. 🦋

The default members of a workspace can be set explicitly with the workspace.default-members key in the root manifest. If you don't set that, then a virtual workspace will include all workspace members (which is equivalent to passing --workspace), and a non-virtual workspace will include only the root crate itself. Periodt.

  • -p *spec*…, --package *spec*… — Build only the specified packages. See cargo-pkgid(1) for the SPEC format. You can drop this flag multiple times and it supports common Unix glob patterns like *, ? and []. BUT — and this is the important part, bestie — to avoid your shell accidentally expanding glob patterns before Cargo even gets to handle 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 legacy, ngl.
  • --exclude *SPEC*… — Exclude the specified packages. This one must be used in conjunction with the --workspace flag — they're a package deal, fr fr. This flag may be specified multiple times and supports common Unix glob patterns like *, ? and []. Same warning though: to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each pattern. 💅

🧚 Target Selection

When no target selection options are given, cargo build will build all binary and library targets of the selected packages. Binaries get skipped if they have required-features that are missing. (Awkward for them, honestly. 💀)

Binary targets are automatically built if there is an integration test or benchmark being selected to build. Why? Because that lets an integration test actually 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 it can use the env macro (https://doc.rust-lang.org/std/macro.env.html) to locate the executable. Cute, right? 🥰

Passing target selection flags will build only the specified targets. Picky. We love that for you.

Heads up bestie: --bin, --example, --test and --bench flags also support common Unix glob patterns like *, ? and []. But to avoid your shell accidentally expanding glob patterns before Cargo handles them, you must use single quotes or double quotes around each glob pattern. Do not skip this. 😭
  • --lib — Build the package's library. The humble little lib. 🍓
  • --bin *name*… — Build the specified binary. This flag may be specified multiple times and supports common Unix glob patterns.
  • --bins — Build all binary targets. All of them. Every single one. 🔥
  • --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 in test mode 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.
  • --bench *name*… — Build the specified benchmark. This flag may be specified multiple times and supports common Unix glob patterns.
  • --benches — Build all targets in benchmark mode that have the bench = true manifest flag set. By default this includes the library and binaries built as benchmarks, and bench targets. Same situation as --tests: 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. Maximum overdrive, no notes. 👑

🌈 Feature Selection

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

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

  • -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. Slay.
  • --all-features — Activate all available features of all selected packages. Go big or go home. 💖
  • --no-default-features — Do not activate the default feature of the selected packages. Sometimes you gotta say no to the default. Boundaries. ✨

🔥 Compilation Options

  • --target triple — Build for the given architecture. The default is the host architecture. The general format of the triple is <arch><sub>-<vendor>-<sys>-<abi>. Run rustc --print target-list for a list of supported targets. This flag may be specified multiple times.

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/guide/build-cache.html) documentation for more details. Don't be surprised when your stuff shows up somewhere else, bestie. 🦋
  • -r, --release — Build optimized artifacts with the release profile. See also the --profile option for choosing a specific profile by name. Release mode: for when you want it to actually be fast. ⭐
  • --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.

🎀 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 where all your little build babies live. 🫶
  • --artifact-dir directory — Copy final artifacts to this directory.
Careful bestie: 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). Give me everything. 😭
  • -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). The introvert option. 🤫
  • --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. Muted, I guess.

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: Instruct Cargo to not include rustc diagnostics in 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. Cannot be used with human or short.
  • --build-plan — Outputs a series of JSON messages to stdout that indicate the commands to run the build.
Unstable alert: 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/5579 for more information.

🌸 Manifest Options 🌸

  • --manifest-path path — tells Cargo exactly where your Cargo.toml lives, bestie. Normally Cargo just vibes and hunts for Cargo.toml in the current directory, or climbs up through parent directories until it finds one. This flag skips the whole scavenger hunt.
  • --ignore-rust-version — just ✨ ignores✨ the rust-version specification in packages. Like it never even said anything.
  • --locked — this one is the strict friend. It asserts that the exact same dependencies and versions get used as when your existing Cargo.lock file was originally generated. Cargo will exit with an error when either of these scenarios shows up:
    • 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. (CI girlies, this one's for you fr.)

  • --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.
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 — the two-for-one special, it's giving bundle deal. Equivalent to specifying both --locked and --offline.

💅 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.
  • --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 (yes, stack them, we love a repeat offender). See the command-line overrides section <https://doc.rust-lang.org/cargo/reference/config.html#command-line-overrides> for more information.
  • -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>). Nightly girlies only, sorry to the rest of us 😭
  • -h, --help — prints help information. The classic. The blueprint. The "just tell me what to do" button. 💖
  • -Z flag — unstable (nightly-only) flags to Cargo. Run cargo -Z help for details.

🎀 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. 🚫
  • --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. It's giving "we don't stop, we keep going" energy.

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.

  • --future-incompat-report — displays a future-incompat report for any future-incompatible warnings produced during execution of this command. A little peek into the future, no cap 🔮

See cargo-report(1)

🌈 ENVIRONMENT 🌈

See the reference <https://doc.rust-lang.org/cargo/reference/environment-variables.html> for details on environment variables that Cargo reads. (Yes, Cargo be reading the room, iykyk.)

⭐ EXIT STATUS ⭐

  • 0: Cargo succeeded. 🎉 we ate.
  • 101: Cargo failed to complete. 😭 it's not giving.

🦋 EXAMPLES 🦋

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

👑 SEE ALSO 👑

cargo(1), cargo-rustc(1)

and that's a wrap on CARGO-BUILD(1) bestie 💖 — this little masterpiece comes to you from the Cargo source, version and date as stamped on the page, signed off with the classic footer tag CARGO-BUILD(1). go build something iconic, you got this 🫶✨

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