Provided by: cargo_0.47.0-1~exp1ubuntu1~16.04.1_amd64 
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 <https://doc.rust-lang.org/cargo/reference/environment-variables.html> or
the build.rustflags config value <https://doc.rust-lang.org/cargo/reference/config.html>.
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 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.
--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. 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.
Feature Selection
The feature flags allow you to control the enabled features for the "current" package. The "current"
package is the package in the current directory, or the one specified in --manifest-path. If running in
the root of a virtual workspace, then the default features are selected for all workspace members, or all
features if --all-features is specified.
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. This flag may be specified multiple times, which enables all specified features.
--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>. Run rustc --print target-list for a list of supported
targets.
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.
--release
Build optimized artifacts with the release profile. 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
<https://doc.rust-lang.org/cargo/reference/config.html>. 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 <https://doc.rust-lang.org/cargo/reference/config.html>.
-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
<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.
• short: Emit shorter, human-readable text messages.
• json: Emit JSON messages to stdout. See the reference
<https://doc.rust-lang.org/cargo/reference/external-tools.html#json-messages> for more details.
• json-diagnostic-short: Ensure the rendered field of JSON messages contains the "short" rendering
from rustc.
• json-diagnostic-rendered-ansi: Ensure the rendered field of JSON messages contains embedded ANSI
color codes for respecting rustc’s default color scheme.
• json-render-diagnostics: Instruct Cargo to not include rustc diagnostics in 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.
Manifest Options
--manifest-path PATH
Path to the Cargo.toml file. By default, Cargo searches for the Cargo.toml file in the current
directory or any parent directory.
--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.
--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 that 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>.
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://github.com/rust-lang/rustup/> for more information about how toolchain overrides work.
-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
<https://doc.rust-lang.org/cargo/reference/config.html>. 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 <https://doc.rust-lang.org/cargo/reference/profiles.html> 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, or any target │ test │ bench │
│in "test" or "bench" mode │ │ │
└───────────────────────────┴─────────────────┴───────────────────┘
Dependencies use the dev/release profiles.
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 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) 2020-06-25 CARGO-RUSTC(1)