Ubuntu Manpage: cargo-rustc — Compile the current package, and pass extra options to the compiler

Provided by: cargo-1.76_1.76.0+dfsg0ubuntu1~bpo10-0ubuntu0.23.10_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.

Binary targets are automatically built if there is an integration test or benchmark being
selected to build. This allows an integration test to 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 that it can use the env macro
<https://doc.rust-lang.org/std/macro.env.html> to locate the executable.

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.

--lib
Build the package’s library.

--bin name…
Build the specified binary. This flag may be specified multiple times and supports
common Unix glob patterns.

--bins
Build all binary targets.

--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.
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 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> 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.

--all-features
Activate all available features of all selected packages.

--no-default-features
Do not activate the default feature of the selected packages.

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.

-r, --release
Build optimized artifacts with the release profile. See also the --profile option for
choosing a specific profile by name.

--profile name
Build with the given profile.

The rustc subcommand will treat the following named profiles with special behaviors:

• check — Builds in the same way as the cargo-check(1) command with the dev profile.

• test — Builds in the same way as the cargo-test(1) command, enabling building in
test mode which will enable tests and enable the test cfg option. See rustc tests
<https://doc.rust-lang.org/rustc/tests/index.html> for more detail.

• bench — Builds in the same was as the cargo-bench(1) command, similar to the test
profile.

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

--ignore-rust-version
Build the target even if the selected Rust compiler is older than the required Rust
version as configured in the project’s rust-version field.

--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.

--crate-type crate-type
Build for the given crate type. This flag accepts a comma-separated list of 1 or more
crate types, of which the allowed values are the same as crate-type field in the
manifest for configuring a Cargo target. See crate-type field
<https://doc.rust-lang.org/cargo/reference/cargo-targets.html#the-crate-type-field>
for possible values.

If the manifest contains a list, and --crate-type is provided, the command-line
argument value will override what is in the manifest.

This flag only works when building a lib or example library target.

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
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
<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.

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://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.

-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.

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

        3. Override crate-type field in Cargo.toml with command-line option:

               cargo rustc --lib --crate-type lib,cdylib