package standard library
go1.22.5 Latest Latest

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Published: Jul 2, 2024 License: BSD-3-Clause Imports: 48 Imported by: 0




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var AllowInstall = func(*Action) error { return nil }

AllowInstall returns a non-nil error if this invocation of the go command is allowed to install a.Target.

The build of cmd/go running under its own test is forbidden from installing to its original GOROOT. The var is exported so it can be set by TestMain.

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var BuildToolchain toolchain = noToolchain{}
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var CmdBuild = &base.Command{
	UsageLine: "go build [-o output] [build flags] [packages]",
	Short:     "compile packages and dependencies",
	Long: `
Build compiles the packages named by the import paths,
along with their dependencies, but it does not install the results.

If the arguments to build are a list of .go files from a single directory,
build treats them as a list of source files specifying a single package.

When compiling packages, build ignores files that end in '_test.go'.

When compiling a single main package, build writes the resulting
executable to an output file named after the last non-major-version
component of the package import path. The '.exe' suffix is added
when writing a Windows executable.
So 'go build example/sam' writes 'sam' or 'sam.exe'.
'go build' writes 'foo' or 'foo.exe', not 'v2.exe'.

When compiling a package from a list of .go files, the executable
is named after the first source file.
'go build ed.go rx.go' writes 'ed' or 'ed.exe'.

When compiling multiple packages or a single non-main package,
build compiles the packages but discards the resulting object,
serving only as a check that the packages can be built.

The -o flag forces build to write the resulting executable or object
to the named output file or directory, instead of the default behavior described
in the last two paragraphs. If the named output is an existing directory or
ends with a slash or backslash, then any resulting executables
will be written to that directory.

The build flags are shared by the build, clean, get, install, list, run,
and test commands:

	-C dir
		Change to dir before running the command.
		Any files named on the command line are interpreted after
		changing directories.
		If used, this flag must be the first one in the command line.
		force rebuilding of packages that are already up-to-date.
		print the commands but do not run them.
	-p n
		the number of programs, such as build commands or
		test binaries, that can be run in parallel.
		The default is GOMAXPROCS, normally the number of CPUs available.
		enable data race detection.
		Supported only on linux/amd64, freebsd/amd64, darwin/amd64, darwin/arm64, windows/amd64,
		linux/ppc64le and linux/arm64 (only for 48-bit VMA).
		enable interoperation with memory sanitizer.
		Supported only on linux/amd64, linux/arm64, linux/loong64, freebsd/amd64
		and only with Clang/LLVM as the host C compiler.
		PIE build mode will be used on all platforms except linux/amd64.
		enable interoperation with address sanitizer.
		Supported only on linux/arm64, linux/amd64, linux/loong64.
		Supported on linux/amd64 or linux/arm64 and only with GCC 7 and higher
		or Clang/LLVM 9 and higher.
		And supported on linux/loong64 only with Clang/LLVM 16 and higher.
		enable code coverage instrumentation.
	-covermode set,count,atomic
		set the mode for coverage analysis.
		The default is "set" unless -race is enabled,
		in which case it is "atomic".
		The values:
		set: bool: does this statement run?
		count: int: how many times does this statement run?
		atomic: int: count, but correct in multithreaded tests;
			significantly more expensive.
		Sets -cover.
	-coverpkg pattern1,pattern2,pattern3
		For a build that targets package 'main' (e.g. building a Go
		executable), apply coverage analysis to each package matching
		the patterns. The default is to apply coverage analysis to
		packages in the main Go module. See 'go help packages' for a
		description of package patterns.  Sets -cover.
		print the names of packages as they are compiled.
		print the name of the temporary work directory and
		do not delete it when exiting.
		print the commands.
	-asmflags '[pattern=]arg list'
		arguments to pass on each go tool asm invocation.
	-buildmode mode
		build mode to use. See 'go help buildmode' for more.
		Whether to stamp binaries with version control information
		("true", "false", or "auto"). By default ("auto"), version control
		information is stamped into a binary if the main package, the main module
		containing it, and the current directory are all in the same repository.
		Use -buildvcs=false to always omit version control information, or
		-buildvcs=true to error out if version control information is available but
		cannot be included due to a missing tool or ambiguous directory structure.
	-compiler name
		name of compiler to use, as in runtime.Compiler (gccgo or gc).
	-gccgoflags '[pattern=]arg list'
		arguments to pass on each gccgo compiler/linker invocation.
	-gcflags '[pattern=]arg list'
		arguments to pass on each go tool compile invocation.
	-installsuffix suffix
		a suffix to use in the name of the package installation directory,
		in order to keep output separate from default builds.
		If using the -race flag, the install suffix is automatically set to race
		or, if set explicitly, has _race appended to it. Likewise for the -msan
		and -asan flags. Using a -buildmode option that requires non-default compile
		flags has a similar effect.
	-ldflags '[pattern=]arg list'
		arguments to pass on each go tool link invocation.
		build code that will be linked against shared libraries previously
		created with -buildmode=shared.
	-mod mode
		module download mode to use: readonly, vendor, or mod.
		By default, if a vendor directory is present and the go version in go.mod
		is 1.14 or higher, the go command acts as if -mod=vendor were set.
		Otherwise, the go command acts as if -mod=readonly were set.
		See for details.
		leave newly-created directories in the module cache read-write
		instead of making them read-only.
	-modfile file
		in module aware mode, read (and possibly write) an alternate go.mod
		file instead of the one in the module root directory. A file named
		"go.mod" must still be present in order to determine the module root
		directory, but it is not accessed. When -modfile is specified, an
		alternate go.sum file is also used: its path is derived from the
		-modfile flag by trimming the ".mod" extension and appending ".sum".
	-overlay file
		read a JSON config file that provides an overlay for build operations.
		The file is a JSON struct with a single field, named 'Replace', that
		maps each disk file path (a string) to its backing file path, so that
		a build will run as if the disk file path exists with the contents
		given by the backing file paths, or as if the disk file path does not
		exist if its backing file path is empty. Support for the -overlay flag
		has some limitations: importantly, cgo files included from outside the
		include path must be in the same directory as the Go package they are
		included from, and overlays will not appear when binaries and tests are
		run through go run and go test respectively.
	-pgo file
		specify the file path of a profile for profile-guided optimization (PGO).
		When the special name "auto" is specified, for each main package in the
		build, the go command selects a file named "default.pgo" in the package's
		directory if that file exists, and applies it to the (transitive)
		dependencies of the main package (other packages are not affected).
		Special name "off" turns off PGO. The default is "auto".
	-pkgdir dir
		install and load all packages from dir instead of the usual locations.
		For example, when building with a non-standard configuration,
		use -pkgdir to keep generated packages in a separate location.
	-tags tag,list
		a comma-separated list of additional build tags to consider satisfied
		during the build. For more information about build tags, see
		'go help buildconstraint'. (Earlier versions of Go used a
		space-separated list, and that form is deprecated but still recognized.)
		remove all file system paths from the resulting executable.
		Instead of absolute file system paths, the recorded file names
		will begin either a module path@version (when using modules),
		or a plain import path (when using the standard library, or GOPATH).
	-toolexec 'cmd args'
		a program to use to invoke toolchain programs like vet and asm.
		For example, instead of running asm, the go command will run
		'cmd args /path/to/asm <arguments for asm>'.
		The TOOLEXEC_IMPORTPATH environment variable will be set,
		matching 'go list -f {{.ImportPath}}' for the package being built.

The -asmflags, -gccgoflags, -gcflags, and -ldflags flags accept a
space-separated list of arguments to pass to an underlying tool
during the build. To embed spaces in an element in the list, surround
it with either single or double quotes. The argument list may be
preceded by a package pattern and an equal sign, which restricts
the use of that argument list to the building of packages matching
that pattern (see 'go help packages' for a description of package
patterns). Without a pattern, the argument list applies only to the
packages named on the command line. The flags may be repeated
with different patterns in order to specify different arguments for
different sets of packages. If a package matches patterns given in
multiple flags, the latest match on the command line wins.
For example, 'go build -gcflags=-S fmt' prints the disassembly
only for package fmt, while 'go build -gcflags=all=-S fmt'
prints the disassembly for fmt and all its dependencies.

For more about specifying packages, see 'go help packages'.
For more about where packages and binaries are installed,
run 'go help gopath'.
For more about calling between Go and C/C++, run 'go help c'.

Note: Build adheres to certain conventions such as those described
by 'go help gopath'. Not all projects can follow these conventions,
however. Installations that have their own conventions or that use
a separate software build system may choose to use lower-level
invocations such as 'go tool compile' and 'go tool link' to avoid
some of the overheads and design decisions of the build tool.

See also: go install, go get, go clean.
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var CmdInstall = &base.Command{
	UsageLine: "go install [build flags] [packages]",
	Short:     "compile and install packages and dependencies",
	Long: `
Install compiles and installs the packages named by the import paths.

Executables are installed in the directory named by the GOBIN environment
variable, which defaults to $GOPATH/bin or $HOME/go/bin if the GOPATH
environment variable is not set. Executables in $GOROOT
are installed in $GOROOT/bin or $GOTOOLDIR instead of $GOBIN.

If the arguments have version suffixes (like @latest or @v1.0.0), "go install"
builds packages in module-aware mode, ignoring the go.mod file in the current
directory or any parent directory, if there is one. This is useful for
installing executables without affecting the dependencies of the main module.
To eliminate ambiguity about which module versions are used in the build, the
arguments must satisfy the following constraints:

- Arguments must be package paths or package patterns (with "..." wildcards).
They must not be standard packages (like fmt), meta-patterns (std, cmd,
all), or relative or absolute file paths.

- All arguments must have the same version suffix. Different queries are not
allowed, even if they refer to the same version.

- All arguments must refer to packages in the same module at the same version.

- Package path arguments must refer to main packages. Pattern arguments
will only match main packages.

- No module is considered the "main" module. If the module containing
packages named on the command line has a go.mod file, it must not contain
directives (replace and exclude) that would cause it to be interpreted
differently than if it were the main module. The module must not require
a higher version of itself.

- Vendor directories are not used in any module. (Vendor directories are not
included in the module zip files downloaded by 'go install'.)

If the arguments don't have version suffixes, "go install" may run in
module-aware mode or GOPATH mode, depending on the GO111MODULE environment
variable and the presence of a go.mod file. See 'go help modules' for details.
If module-aware mode is enabled, "go install" runs in the context of the main

When module-aware mode is disabled, non-main packages are installed in the
directory $GOPATH/pkg/$GOOS_$GOARCH. When module-aware mode is enabled,
non-main packages are built and cached but not installed.

Before Go 1.20, the standard library was installed to
Starting in Go 1.20, the standard library is built and cached but not installed.
Setting GODEBUG=installgoroot=all restores the use of

For more about build flags, see 'go help build'.

For more about specifying packages, see 'go help packages'.

See also: go build, go get, go clean.
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var ExecCmd []string

ExecCmd is the command to use to run user binaries. Normally it is empty, meaning run the binaries directly. If cross-compiling and running on a remote system or simulator, it is typically go_GOOS_GOARCH_exec, with the target GOOS and GOARCH substituted. The -exec flag overrides these defaults.

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var GccgoName, GccgoBin string
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var ToolchainVersion = runtime.Version()

Tests can override this by setting $TESTGO_TOOLCHAIN_VERSION.

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var VetExplicit bool

VetExplicit records whether the vet flags were set explicitly on the command line.

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var VetFlags []string

VetFlags are the default flags to pass to vet. The caller is expected to set them before executing any vet actions.

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var VetTool string

VetTool is the path to an alternate vet tool binary. The caller is expected to set it (if needed) before executing any vet actions.


func AddBuildFlags

func AddBuildFlags(cmd *base.Command, mask BuildFlagMask)

AddBuildFlags adds the flags common to the build, clean, get, install, list, run, and test commands.

func AddCoverFlags added in go1.20

func AddCoverFlags(cmd *base.Command, coverProfileFlag *string)

AddCoverFlags adds coverage-related flags to "cmd". If the CoverageRedesign experiment is enabled, we add -cover{mode,pkg} to the build command and only -coverprofile to the test command. If the CoverageRedesign experiment is disabled, -cover* flags are added only to the test command.

func BuildActionCoverMetaFile added in go1.22.0

func BuildActionCoverMetaFile(runAct *Action) (string, error)

BuildActionCoverMetaFile locates and returns the path of the meta-data file written by the "go tool cover" step as part of the build action for the "go test -cover" run action 'runAct'. Note that if the package has no functions the meta-data file will exist but will be empty; in this case the return is an empty string.

func BuildInit added in go1.10

func BuildInit()

func BuildInstallFunc

func BuildInstallFunc(b *Builder, ctx context.Context, a *Action) (err error)

BuildInstallFunc is the action for installing a single package or executable.

func CheckGOOSARCHPair added in go1.14

func CheckGOOSARCHPair(goos, goarch string) error

func FindExecCmd

func FindExecCmd() []string

FindExecCmd derives the value of ExecCmd to use. It returns that value and leaves ExecCmd set for direct use.

func InstallPackages

func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Package)

func WriteCoverMetaFilesFile added in go1.22.0

func WriteCoverMetaFilesFile(b *Builder, ctx context.Context, a *Action) error

WriteCoverMetaFilesFile writes out a summary file ("meta-files file") as part of the action function for the "writeCoverMeta" pseudo action employed during "go test -coverpkg" runs where there are multiple tests and multiple packages covered. It builds up a table mapping package import path to meta-data file fragment and writes it out to a file where it can be read by the various test run actions. Note that this function has to be called A) after the build actions are complete for all packages being tested, and B) before any of the "run test" actions for those packages happen. This requirement is enforced by adding making this action ("a") dependent on all test package build actions, and making all test run actions dependent on this action.

func WriteCoveragePercent added in go1.22.0

func WriteCoveragePercent(b *Builder, runAct *Action, mf string, w io.Writer) error

WriteCoveragePercent writes out to the writer 'w' a "percent statements covered" for the package whose test-run action is 'runAct', based on the meta-data file 'mf'. This helper is used in cases where a user runs "go test -cover" on a package that has functions but no tests; in the normal case (package has tests) the percentage is written by the test binary when it runs.

func WriteCoverageProfile added in go1.22.0

func WriteCoverageProfile(b *Builder, runAct *Action, mf, outf string, w io.Writer) error

WriteCoverageProfile writes out a coverage profile fragment for the package whose test-run action is 'runAct'; content is written to the file 'outf' based on the coverage meta-data info found in 'mf'. This helper is used in cases where a user runs "go test -cover" on a package that has functions but no tests.


type Action

type Action struct {
	Mode       string        // description of action operation
	Package    *load.Package // the package this action works on
	Deps       []*Action     // actions that must happen before this one
	Actor      Actor         // the action itself (nil = no-op)
	IgnoreFail bool          // whether to run f even if dependencies fail
	TestOutput *bytes.Buffer // test output buffer
	Args       []string      // additional args for runProgram

	TryCache func(*Builder, *Action) bool // callback for cache bypass

	// Generated files, directories.
	Objdir string // directory for intermediate objects
	Target string // goal of the action: the created package or executable

	VetxOnly bool // Mode=="vet": only being called to supply info about dependencies

	Failed bool // whether the action failed
	// contains filtered or unexported fields

An Action represents a single action in the action graph.

func (*Action) BuildActionID added in go1.10

func (a *Action) BuildActionID() string

BuildActionID returns the action ID section of a's build ID.

func (*Action) BuildContentID added in go1.10

func (a *Action) BuildContentID() string

BuildContentID returns the content ID section of a's build ID.

func (*Action) BuildID added in go1.10

func (a *Action) BuildID() string

BuildID returns a's build ID.

func (*Action) BuiltTarget added in go1.10

func (a *Action) BuiltTarget() string

BuiltTarget returns the actual file that was built. This differs from Target when the result was cached.

type Actor added in go1.20

type Actor interface {
	Act(*Builder, context.Context, *Action) error

An Actor runs an action.

type ActorFunc added in go1.20

type ActorFunc func(*Builder, context.Context, *Action) error

An ActorFunc is an Actor that calls the function.

func (ActorFunc) Act added in go1.20

func (f ActorFunc) Act(b *Builder, ctx context.Context, a *Action) error

type BuildFlagMask added in go1.14

type BuildFlagMask int
const (
	DefaultBuildFlags BuildFlagMask = 0
	OmitModFlag       BuildFlagMask = 1 << iota

type BuildMode

type BuildMode int

BuildMode specifies the build mode: are we just building things or also installing the results?

const (
	ModeBuild BuildMode = iota

	ModeVetOnly = 1 << 8

type Builder

type Builder struct {
	WorkDir string // the temporary work directory (ends in filepath.Separator)

	IsCmdList           bool // running as part of go list; set p.Stale and additional fields below
	NeedError           bool // list needs p.Error
	NeedExport          bool // list needs p.Export
	NeedCompiledGoFiles bool // list needs p.CompiledGoFiles
	AllowErrors         bool // errors don't immediately exit the program
	// contains filtered or unexported fields

A Builder holds global state about a build. It does not hold per-package state, because we build packages in parallel, and the builder is shared.

func NewBuilder added in go1.18.6

func NewBuilder(workDir string) *Builder

NewBuilder returns a new Builder ready for use.

If workDir is the empty string, NewBuilder creates a WorkDir if needed and arranges for it to be removed in case of an unclean exit. The caller must Close the builder explicitly to clean up the WorkDir before a clean exit.

func (*Builder) AutoAction added in go1.10

func (b *Builder) AutoAction(mode, depMode BuildMode, p *load.Package) *Action

AutoAction returns the "right" action for go build or go install of p.

func (*Builder) BackgroundShell added in go1.22.0

func (b *Builder) BackgroundShell() *Shell

BackgroundShell returns a Builder-wide Shell that's not bound to any Action. Try not to use this unless there's really no sensible Action available.

func (*Builder) CFlags

func (b *Builder) CFlags(p *load.Package) (cppflags, cflags, cxxflags, fflags, ldflags []string, err error)

CFlags returns the flags to use when invoking the C, C++ or Fortran compilers, or cgo.

func (*Builder) Close added in go1.20

func (b *Builder) Close() error

func (*Builder) CompileAction added in go1.10

func (b *Builder) CompileAction(mode, depMode BuildMode, p *load.Package) *Action

CompileAction returns the action for compiling and possibly installing (according to mode) the given package. The resulting action is only for building packages (archives), never for linking executables. depMode is the action (build or install) to use when building dependencies. To turn package main into an executable, call b.Link instead.

func (*Builder) CovData added in go1.22.0

func (b *Builder) CovData(a *Action, cmdargs ...any) ([]byte, error)

CovData invokes "go tool covdata" with the specified arguments as part of the execution of action 'a'.

func (*Builder) Do

func (b *Builder) Do(ctx context.Context, root *Action)

Do runs the action graph rooted at root.

func (*Builder) GccCmd

func (b *Builder) GccCmd(incdir, workdir string) []string

GccCmd returns a gcc command line prefix defaultCC is defined in zdefaultcc.go, written by cmd/dist.

func (*Builder) GxxCmd

func (b *Builder) GxxCmd(incdir, workdir string) []string

GxxCmd returns a g++ command line prefix defaultCXX is defined in zdefaultcc.go, written by cmd/dist.

func (*Builder) LinkAction added in go1.10

func (b *Builder) LinkAction(mode, depMode BuildMode, p *load.Package) *Action

LinkAction returns the action for linking p into an executable and possibly installing the result (according to mode). depMode is the action (build or install) to use when compiling dependencies.

func (*Builder) NewObjdir added in go1.10

func (b *Builder) NewObjdir() string

NewObjdir returns the name of a fresh object directory under b.WorkDir. It is up to the caller to call b.Mkdir on the result at an appropriate time. The result ends in a slash, so that file names in that directory can be constructed with direct string addition.

NewObjdir must be called only from a single goroutine at a time, so it is safe to call during action graph construction, but it must not be called during action graph execution.

func (*Builder) PkgconfigCmd

func (b *Builder) PkgconfigCmd() string

PkgconfigCmd returns a pkg-config binary name defaultPkgConfig is defined in zdefaultcc.go, written by cmd/dist.

func (*Builder) Shell added in go1.22.0

func (b *Builder) Shell(a *Action) *Shell

Shell returns a shell for running commands on behalf of Action a.

func (*Builder) VetAction added in go1.10

func (b *Builder) VetAction(mode, depMode BuildMode, p *load.Package) *Action

VetAction returns the action for running go vet on package p. It depends on the action for compiling p. If the caller may be causing p to be installed, it is up to the caller to make sure that the install depends on (runs after) vet.

type Shell added in go1.22.0

type Shell struct {
	// contains filtered or unexported fields

A Shell runs shell commands and performs shell-like file system operations.

Shell tracks context related to running commands, and form a tree much like context.Context.

func NewShell added in go1.22.0

func NewShell(workDir string, print func(a ...any) (int, error)) *Shell

NewShell returns a new Shell.

Shell will internally serialize calls to the print function. If print is nil, it defaults to printing to stderr.

func (*Shell) CopyFile added in go1.22.0

func (sh *Shell) CopyFile(dst, src string, perm fs.FileMode, force bool) error

copyFile is like 'cp src dst'.

func (*Shell) Mkdir added in go1.22.0

func (sh *Shell) Mkdir(dir string) error

Mkdir makes the named directory.

func (*Shell) Print added in go1.22.0

func (sh *Shell) Print(a ...any)

Print emits a to this Shell's output stream, formatting it like fmt.Print. It is safe to call concurrently.

func (*Shell) RemoveAll added in go1.22.0

func (sh *Shell) RemoveAll(paths ...string) error

RemoveAll is like 'rm -rf'. It attempts to remove all paths even if there's an error, and returns the first error.

func (*Shell) ShowCmd added in go1.22.0

func (sh *Shell) ShowCmd(dir string, format string, args ...any)

ShowCmd prints the given command to standard output for the implementation of -n or -x.

ShowCmd also replaces the name of the current script directory with dot (.) but only when it is at the beginning of a space-separated token.

If dir is not "" or "/" and not the current script directory, ShowCmd first prints a "cd" command to switch to dir and updates the script directory.

func (sh *Shell) Symlink(oldname, newname string) error

Symlink creates a symlink newname -> oldname.

func (*Shell) WithAction added in go1.22.0

func (sh *Shell) WithAction(a *Action) *Shell

WithAction returns a Shell identical to sh, but bound to Action a.

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