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 ifprovided) will be compiled along with all of its dependencies. The specifiedARGS will all be passed to the final compiler invocation, not any of thedependencies. Note that the compiler will still unconditionally receivearguments such as -L, —extern, and —crate-type, and the specifiedARGS will simply be added to the compiler invocation.

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

This command requires that only one target is being compiled when additionalarguments are provided. If more than one target is available for the currentpackage the filters of —lib, —bin, etc, must be used to select whichtarget is compiled.To pass flags to all compiler processes spawned by Cargo, use the RUSTFLAGSenvironment variable or the build.rustflagsconfig value.

OPTIONS

Package Selection

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

  • -pSPEC
  • —packageSPEC
  • The package to build. See cargo-pkgid(1) forthe SPEC format.

Target Selection

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

Passing target selection flags will build only thespecified targets.

  • —lib

  • Build the package’s library.

  • —binNAME…​

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

  • —bins

  • Build all binary targets.

  • —exampleNAME…​

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

  • —examples

  • Build all example targets.

  • —testNAME…​

  • Build the specified integration test. This flag may be specified multipletimes.

  • —tests

  • Build all targets in test mode that have the test = true manifestflag set. By default this includes the library and binaries built asunittests, and integration tests. Be aware that this will also build anyrequired dependencies, so the lib target may be built twice (once as aunittest, and once as a dependency for binaries, integration tests, etc.).Targets may be enabled or disabled by setting the test flag in themanifest settings for the target.

  • —benchNAME…​

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

  • —benches

  • Build all targets in benchmark mode that have the bench = truemanifest flag set. By default this includes the library and binaries builtas benchmarks, and bench targets. Be aware that this will also build anyrequired dependencies, so the lib target may be built twice (once as abenchmark, and once as a dependency for binaries, benchmarks, etc.).Targets may be enabled or disabled by setting the bench flag in themanifest settings for the target.

  • —all-targets

  • Build all targets. This is equivalent to specifying —lib —bins—tests —benches —examples.

Feature Selection

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

  • —featuresFEATURES

  • Space or comma separated list of features to activate. These features onlyapply to the current directory’s package. Features of direct dependenciesmay 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’spackage.

Compilation Options

  • —targetTRIPLE
  • Build for the given architecture. The default is the hostarchitecture. The general format of the triple is<arch><sub>-<vendor>-<sys>-<abi>. Run rustc —print target-list for alist of supported targets.

This may also be specified with the build.targetconfig value.

  • —release
  • Build optimized artifacts with the release profile. See thePROFILES section for details on how this affects profile selection.

Output Options

  • —target-dirDIRECTORY
  • Directory for all generated artifacts and intermediate files. May also bespecified with the CARGO_TARGET_DIR environment variable, or thebuild.target-dir config value. Defaultsto target in the root of the workspace.

Display Options

  • -v
  • —verbose

  • Use verbose output. May be specified twice for "very verbose" output whichincludes extra output such as dependency warnings and build script output.May also be specified with the term.verboseconfig value.

  • -q

  • —quiet

  • No output printed to stdout.

  • —colorWHEN

  • Control when colored output is used. Valid values:

  • auto (default): Automatically detect if color support is available on theterminal.

  • always: Always display colors.

  • never: Never display colors.

May also be specified with the term.colorconfig value.

  • —message-formatFMT
  • The output format for diagnostic messages. Can be specified multiple timesand 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.

  • json-diagnostic-short: Ensure the rendered field of JSON messages containsthe "short" rendering from rustc.

  • json-diagnostic-rendered-ansi: Ensure the rendered field of JSON messagescontains embedded ANSI color codes for respecting rustc’s default colorscheme.

  • json-render-diagnostics: Instruct Cargo to not include rustc diagnostics inin JSON messages printed, but instead Cargo itself should render theJSON diagnostics coming from rustc. Cargo’s own JSON diagnostics and otherscoming from rustc are still emitted.

Manifest Options

  • —manifest-pathPATH

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

  • —frozen

  • —locked
  • Either of these flags requires that the Cargo.lock file isup-to-date. If the lock file is missing, or it needs to be updated, Cargo willexit with an error. The —frozen flag also prevents Cargo fromattempting to access the network to determine if it is out-of-date.

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

  • —offline
  • Prevents Cargo from accessing the network for any reason. Without thisflag, Cargo will stop with an error if it needs to access the network andthe network is not available. With this flag, Cargo will attempt toproceed without the network if possible.

Beware that this may result in different dependency resolution than onlinemode. Cargo will restrict itself to crates that are downloaded locally, evenif 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 goingoffline.

May also be specified with the net.offline config value.

Common Options

  • -h
  • —help

  • Prints help information.

  • -ZFLAG…​

  • Unstable (nightly-only) flags to Cargo. Run cargo -Z help fordetails.

Miscellaneous Options

  • -jN
  • —jobsN
  • Number of parallel jobs to run. May also be specified with thebuild.jobs config value. Defaults tothe number of CPUs.

PROFILES

Profiles may be used to configure compiler options such as optimization levelsand debug settings. Seethe referencefor more details.

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

TargetDefault Profile—release Profile
lib, bin, exampledevrelease
test, bench, or any target in "test" or "bench" modetestbench

Dependencies use the dev/release profiles.

ENVIRONMENT

See the reference fordetails on environment variables that Cargo reads.

Exit Status

  • 0

  • Cargo succeeded.

  • 101

  • Cargo failed to complete.

EXAMPLES

  • Check if your package (not including dependencies) uses unsafe code:
  1. cargo rustc --lib -- -D unsafe-code
  • Try an experimental flag on the nightly compiler, such as this which printsthe size of every type:
  1. cargo rustc --lib -- -Z print-type-sizes

SEE ALSO

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