CARGO-CHECK(1)

📦 version 1.88.0, in ubuntu questing

CARGO-CHECK(1) 💅

okay bestie, you found the General Commands Manual page for cargo-check, and honestly? it's giving "underrated icon." buckle up 🎀

✨ NAME ✨

cargo-check — Check the current package 🦋

✨ SYNOPSIS ✨

cargo check [options]

✨ DESCRIPTION ✨

So here's the vibe: cargo check checks a local package and all of its dependencies for errors. and like, that's basically it compiling your packages without doing the final step of code generation — which is why it's faster than running cargo build. slay, honestly.

the compiler will save metadata files to disk so that future runs reuse them if the source hasn't been modified. icon behavior fr fr. 🫶

but wait, important caveat bestie: some diagnostics and errors are only emitted during code generation, so they inherently won't be reported with cargo check. it's not a bug, it's just the assignment. 😭

✨ OPTIONS ✨

📦 Package Selection

okay so by default, when you give no package selection options, the packages selected depend on the selected manifest file (which is based on the current working directory if --manifest-path isn't given). if the manifest is the root of a workspace then the workspace's default members get selected, otherwise only the package defined by the manifest will be selected. that's the rule 💅

the default members of a workspace can be set explicitly with the workspace.default-members key in the root manifest. if that's not set, then:

  • a virtual workspace will include all workspace members (equivalent to passing --workspace)
  • a non-virtual workspace will include only the root crate itself
  • -p *spec*…, --package *spec*… — Check only the specified packages. See cargo-pkgid(1) for the SPEC format. 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. quote ur globs bestie i'm begging 😭
  • --workspace — Check all members in the workspace. 👑
  • --all — Deprecated alias for --workspace. deprecated!! like it still works but. girl. just use --workspace.
  • --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. ✨

🎯 Target Selection

when no target selection options are given, cargo check will check all binary and library targets of the selected packages. Binaries are skipped if they have required-features that are missing. (yes it just. skips them. no drama.)

passing target selection flags will check only the specified targets.

note: --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 — Check the package's library. 📚
  • --bin *name*… — Check the specified binary. This flag may be specified multiple times and supports common Unix glob patterns.
  • --bins — Check all binary targets. ✨
  • --example *name*… — Check the specified example. This flag may be specified multiple times and supports common Unix glob patterns.
  • --examples — Check all example targets. 🌸
  • --test *name*… — Check the specified integration test. This flag may be specified multiple times and supports common Unix glob patterns.
  • --tests — Check 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. double build, double the vibe check 🧚
  • --bench *name*… — Check the specified benchmark. This flag may be specified multiple times and supports common Unix glob patterns.
  • --benches — Check 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 — Check all targets. This is equivalent to specifying --lib --bins --tests --benches --examples. the whole menu, no skips 🍓

🎀 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.

see the features documentation: https://doc.rust-lang.org/cargo/reference/features.html#command-line-feature-options

  • *-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. go big or go home 🌈
  • --no-default-features — Do not activate the default feature of the selected packages. 💀

⚙️ Compilation Options

  • *--target *triple** — Check 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: 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 for more details: https://doc.rust-lang.org/cargo/reference/build-cache.html
  • -r, --release — Check optimized artifacts with the release profile. See also the --profile option for choosing a specific profile by name. 🔥
  • --profile name` — Check with the given profile.

As a special case, specifying the test profile will also enable checking in test mode which will enable checking tests and enable the test cfg option. See rustc tests: https://doc.rust-lang.org/rustc/tests/index.html

See the reference for more details on profiles: https://doc.rust-lang.org/cargo/reference/profiles.html

  • --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_DIRenvironment variable, or thebuild.target-dirconfig value:https://doc.rust-lang.org/cargo/reference/config.htmlDefaults totarget` in the root of the workspace. 📁

🖥️ 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
  • -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 🤫
  • --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 for more details: https://doc.rust-lang.org/cargo/reference/external-tools.html#json-messages — 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.
lowkey watch out — those conflicts are real, bestie. don't mix human and short and then act surprised 🙈

📜 Manifest Options

  • *--manifest-path *path** — Path to the Cargo.tomlfile. By default, Cargo searches for theCargo.toml` file in the current directory or any parent directory. 🕵️♀️
  • --ignore-rust-version — Ignore rust-version specification in packages. living dangerously, iconic 💅
  • --locked — 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.
fr fr, heed this one: it's an assertion, and if reality doesn't match, Cargo bails. no cap.

It may be used in environments where deterministic builds are desired, such as in CI pipelines. No cap, that's the vibe. ✨

  • --offline — okay so this one literally says "no network, no problem" to Cargo. It 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 — Equivalent to specifying both --locked and --offline. That's it. That's the tweet. 💅
  • --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).

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. 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).

  • -h, --help — Prints help information. Simple as that. 🫶
  • -Z flag — Unstable (nightly-only) flags to Cargo. Run cargo -Z help for details. iykyk. 💅

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.

For example if the current package depends on dependencies fails and works, one of which fails to build, cargo check -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 check -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.

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.

EXIT STATUS 💀

  • 0: Cargo succeeded. 🎉
  • 101: Cargo failed to complete. 😭

EXAMPLES ✨

  1. Check the local package for errors:
cargo check
  1. Check all targets, including unit tests:
cargo check --all-targets --profile=test

SEE ALSO 🔗

cargo(1), cargo-build(1)

And that's the footer, bestie — CARGO-CHECK(1), straight from the Cargo manual. Version and date? Check your local manpage, but this is the vibe. Periodt. 💅✨

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