cargo rustc

NAME

cargo-rustc - Compile the current package, and pass extra options to the compiler

SYNOPSIS

cargo rustc [OPTIONS] [-- ARGS]

DESCRIPTION

The specified target for the current package (or package specified by -p if provided) will be compiled along with all of its dependencies. The specified ARGS will all be passed to the final compiler invocation, not any of the dependencies. Note that the compiler will still unconditionally receive arguments such as -L, --extern, and --crate-type, and the specified ARGS will simply be added to the compiler invocation.

See https://doc.rust-lang.org/rustc/index.html for documentation on rustc flags.

This command requires that only one target is being compiled when additional arguments are provided. If more than one target is available for the current package the filters of --lib, --bin, etc, must be used to select which target is compiled. To pass flags to all compiler processes spawned by Cargo, use the RUSTFLAGS environment variable or the build.rustflags config value.

OPTIONS

Package Selection

By default, the package in the current working directory is selected. The -p flag can be used to choose a different package in a workspace.

-p SPEC
--package SPEC

The package to build. See cargo-pkgid(1) for the SPEC format.

Target Selection

When no target selection options are given, cargo rustc will build all binary and library targets of the selected package.

Passing target selection flags will build only the specified targets.

--lib

Build the package’s library.

--bin NAME…​

Build the specified binary. This flag may be specified multiple times.

--bins

Build all binary targets.

--example NAME…​

Build the specified example. This flag may be specified multiple times.

--examples

Build all example targets.

--test NAME…​

Build the specified integration test. This flag may be specified multiple times.

--tests

Build all tests. This includes both unit tests for libraries and binaries and integration tests. Targets may be disabled by setting test = false in the manifest settings for the target. Targets (such as examples) may be explicitly included by setting test = true in the target settings.

--bench NAME…​

Build the specified benchmark. This flag may be specified multiple times.

--benches

Build all benchmarks. This includes both unit benchmarks for libraries and binaries and bench targets. Targets may be disabled by setting bench = false in the manifest settings for the target. Targets (such as examples) may be explicitly included by setting bench = true in the target settings.

--all-targets

Build all targets.

Feature Selection

When no feature options are given, the default feature is activated for every selected package.

--features FEATURES

Space or comma separated list of features to activate. These features only apply to the current directory’s package. Features of direct dependencies may be enabled with <dep-name>/<feature-name> syntax.

--all-features

Activate all available features of all selected packages.

--no-default-features

Do not activate the default feature of the current directory’s package.

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> where:

  • arch = The base CPU architecture, for example x86_64, i686, arm, thumb, mips, etc.

  • sub = The CPU sub-architecture, for example arm has v7, v7s, v5te, etc.

  • vendor = The vendor, for example unknown, apple, pc, linux, etc.

  • sys = The system name, for example linux, windows, etc. none is typically used for bare-metal without an OS.

  • abi = The ABI, for example gnu, android, eabi, etc.

Some parameters may be omitted. Run rustc --print target-list for a list of supported targets.

This may also be specified with the build.target config value.

--release

Build artifacts in release mode, with optimizations. See the PROFILES section for details on how this affects profile selection.

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. Defaults to target 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.

-q
--quiet

No output printed to stdout.

--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.

--message-format FMT

The output format for diagnostic messages. Valid values:

  • human (default): Display in a human-readable text format.

  • json: Emit JSON messages to stdout.

  • short: Emit shorter, human-readable text messages.

Manifest Options

--manifest-path PATH

Path to the Cargo.toml file. By default, Cargo searches in the current directory or any parent directory for the Cargo.toml file.

--frozen
--locked

Either of these flags requires that the Cargo.lock file is up-to-date. If the lock file is missing, or it needs to be updated, Cargo will exit with an error. The --frozen flag also prevents Cargo from attempting to access the network to determine if it is out-of-date.

These may be used in environments where you want to assert that the Cargo.lock file is up-to-date (such as a CI build) or want to avoid network access.

Common Options

-h
--help

Prints help information.

-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. Defaults to the number of CPUs.

PROFILES

Profiles may be used to configure compiler options such as optimization levels and debug settings. See the reference for more details.

Profile selection depends on the target and crate being built. By default the dev or test profiles are used. If the --release flag is given, then the release or bench profiles are used.

Target Default Profile --release Profile

lib, bin, example

dev

release

test, bench

test

bench

Dependencies use the dev/release profiles.

ENVIRONMENT

See the reference for details on environment variables that Cargo reads.

Exit Status

0

Cargo succeeded.

101

Cargo failed to complete.

EXAMPLES

  1. Check if your package (not including dependencies) uses unsafe code:

    cargo rustc --lib -- -D unsafe-code

  2. Try an experimental flag on the nightly compiler, such as this which prints the size of every type:

    cargo rustc --lib -- -Z print-type-sizes

SEE ALSO

cargo(1), cargo-build(1), rustc(1)