CARGO-BUILD(1)

📦 version 1.79.0, in ubuntu jammy, ubuntu noble

👑 CARGO-BUILD 👑

okay bestie, welcome to the cargo-build page — straight out of the General Commands Manual, delivered with group-chat energy. this one is long, so hydrate first 💖

🎀 NAME 🎀

cargo-build — Compile the current package

🎀 SYNOPSIS 🎀

cargo build [options]

🎀 DESCRIPTION 🎀

Compile local packages and all of their dependencies. so it builds your local packages and every single thing they depend on. the whole tree, no crumbs left behind. 🌸

✨ OPTIONS ✨

💅 Package Selection 💅

okay so the default tea first: when you don't pass any package-selection options, which packages get picked depends on the selected manifest file — and which manifest is selected depends on your current working directory, unless you passed --manifest-path. If that manifest is the root of a workspace, then the workspace's default members get selected. Otherwise, only the package that the manifest defines gets selected. that's the rule, periodt. 🫶

You can set a workspace's default members explicitly with the workspace.default-members key in the root manifest. If you never set it: a virtual workspace includes all workspace members (literally the same thing as passing --workspace), and a non-virtual workspace includes only the root crate itself. no cap. ✨

  • -p spec…, --package spec… — Build only the specified packages. For the SPEC format, go look at cargo-pkgid(1). This flag may be specified multiple times and it supports common Unix glob patterns like *, ? and [].
⚠️ bestie, listen — to avoid your shell accidentally expanding glob patterns before Cargo gets to handle them, you must wrap each pattern in single quotes or double quotes. the shell is not your friend here. 💀
  • --workspace — Build all members in the workspace. everybody's coming. 👑
  • --all — Deprecated alias for --workspace. it's giving legacy, use the new one. 🙈
  • --exclude SPEC… — Exclude the specified packages. Must be used in conjunction with the --workspace flag — it does not work solo, do not try it. This flag may be specified multiple times and supports common Unix glob patterns like *, ? and [].
⚠️ same warning as above, same energy: 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 you give no target selection options at all, cargo build will build all binary and library targets of the selected packages. Binaries get skipped if they have required-features that are missing. bye to those ones. ✌️

Binary targets are automatically built if there's an integration test or benchmark being selected to build — this is so an integration test can 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. iykyk. 🦋

Passing target selection flags will build only the specified targets.

⚠️ 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. literally the same warning, do not skip it. 🌸
  • --lib — Build the package's library. just the 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. 🔥
  • --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. Heads up though — 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. And yes, same situation — 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 everything bagel. 🥯

💅 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. cute little default behaviour. ✨

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. stack them up. 💅
  • --all-features — Activate all available features of all selected packages. go absolutely feral. 🔥
  • --no-default-features — Do not activate the default feature of the selected packages. opting out, respectfully. 🎀

💅 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 documentation (https://doc.rust-lang.org/cargo/guide/build-cache.html) for more details. don't be surprised when your files show 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. the glow-up build. 👑
  • --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.
  • --out-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). say more, bestie. 🗣️
  • -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. iconic. 🤫
  • --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: 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.
⚠️ 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 — points Cargo at the Cargo.toml file you want it to use. If you don't say anything, Cargo goes looking for a Cargo.toml in the current directory, and then keeps walking up through every parent directory until it finds one. sneaky little detective behavior, love that for it 🔍
  • --ignore-rust-version — just... ignores the rust-version specification in packages. pretend you didn't see it bestie 🙈
  • --locked — swears up and down that the exact same dependencies and versions get used as when the existing Cargo.lock file was originally generated. Cargo will bail with an error when either of these scenarios shows up:
    • The lock file is missing. 💀
    • Cargo attempted to change the lock file because of a different dependency resolution.

It's giving "do NOT touch my lockfile." Use it in environments where you want deterministic builds, like CI pipelines. CI girlies, this one's for you ✨

  • --offline — stops Cargo from touching the network for any reason, periodt. Without this flag, Cargo just stops with an error if it needs network access and the network isn't available. With the flag, Cargo tries to keep going without the network if it possibly can. 🛜🚫
Careful bestie!! This may result in a different dependency resolution than online mode. Cargo restricts 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 cargo-fetch(1) to download dependencies before going offline. prep ahead, main character energy 💅

May also be specified with the net.offline config value <https://doc.rust-lang.org/cargo/reference/config.html>.

  • --frozen — literally just the equivalent of specifying both --locked and --offline at the same time. two for one, ate 🍓

✨ Common Options ✨

  • +toolchain — if Cargo was installed with rustup, and the first argument to cargo begins with +, Cargo reads it as a rustup toolchain name (like +stable or +nightly). See the rustup documentation <https://rust-lang.github.io/rustup/overrides.html> for more info on how toolchain overrides work. fancy ✨
  • --config KEY=VALUE or PATH — overrides a Cargo configuration value. The argument should be in TOML syntax of KEY=VALUE, or handed over as a path to an extra configuration file. This flag can be specified multiple times. See the command-line overrides section <https://doc.rust-lang.org/cargo/reference/config.html#command-line-overrides> for more info. stack 'em up 🧚
  • -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), and also 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.
Heads up: 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 only, no cap 🌙
  • -h, --help — prints help information. the classic 🫶
  • -Z flag — unstable (nightly-only) flags for Cargo. Run cargo -Z help for the details. chaos mode, opt-in only 🔥

✨ Miscellaneous Options ✨

  • -j N, --jobs N — the 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 it's negative, it sets the maximum number of parallel jobs to the number of logical CPUs plus the value you provided. If a string default is provided, it sets the value back to defaults. Should not be 0. zero is not the vibe 🚫
  • --keep-going — builds as many crates in the dependency graph as possible, instead of aborting the whole build on the first one that fails to build. resilience queen 👑

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. the way that --keep-going just does not give up… obsessed 💖

  • --future-incompat-report — displays a future-incompat report for any future-incompatible warnings produced during execution of this command. a lil peek into the future 🔮

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. env vars are lowkey the whole plot 🦋

💖 EXIT STATUS 💖

  • 0: Cargo succeeded. slay ✨
  • 101: Cargo failed to complete. oof 😭

⭐ EXAMPLES ⭐

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

go build something iconic bestie 🎀

🌸 SEE ALSO 🌸

cargo(1), cargo-rustc(1)

And that's the whole page, babe 💜 — this was CARGO-BUILD(1), part of the Cargo documentation set. Go forth and compile, and remember: the lockfile is sacred. 🫶✨

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