package build

Import Path
	go/build (on go.dev)

Dependency Relation
	imports 25 packages, and imported by one package


Involved Source Files

	      build.go
	
		Package build gathers information about Go packages.

		Go Path

		The Go path is a list of directory trees containing Go source code.
		It is consulted to resolve imports that cannot be found in the standard
		Go tree. The default path is the value of the GOPATH environment
		variable, interpreted as a path list appropriate to the operating system
		(on Unix, the variable is a colon-separated string;
		on Windows, a semicolon-separated string;
		on Plan 9, a list).

		Each directory listed in the Go path must have a prescribed structure:

		The src/ directory holds source code. The path below 'src' determines
		the import path or executable name.

		The pkg/ directory holds installed package objects.
		As in the Go tree, each target operating system and
		architecture pair has its own subdirectory of pkg
		(pkg/GOOS_GOARCH).

		If DIR is a directory listed in the Go path, a package with
		source in DIR/src/foo/bar can be imported as "foo/bar" and
		has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a"
		(or, for gccgo, "DIR/pkg/gccgo/foo/libbar.a").

		The bin/ directory holds compiled commands.
		Each command is named for its source directory, but only
		using the final element, not the entire path. That is, the
		command with source in DIR/src/foo/quux is installed into
		DIR/bin/quux, not DIR/bin/foo/quux. The foo/ is stripped
		so that you can add DIR/bin to your PATH to get at the
		installed commands.

		Here's an example directory layout:

		GOPATH=/home/user/gocode

		/home/user/gocode/
		    src/
		        foo/
		            bar/               (go code in package bar)
		                x.go
		            quux/              (go code in package main)
		                y.go
		    bin/
		        quux                   (installed command)
		    pkg/
		        linux_amd64/
		            foo/
		                bar.a          (installed package object)

		Build Constraints

		A build constraint, also known as a build tag, is a line comment that begins

		//go:build

		that lists the conditions under which a file should be included in the
		package. Build constraints may also be part of a file's name
		(for example, source_windows.go will only be included if the target
		operating system is windows).

		See 'go help buildconstraint'
		(https://golang.org/cmd/go/#hdr-Build_constraints) for details.

		Binary-Only Packages

		In Go 1.12 and earlier, it was possible to distribute packages in binary
		form without including the source code used for compiling the package.
		The package was distributed with a source file not excluded by build
		constraints and containing a "//go:binary-only-package" comment. Like a
		build constraint, this comment appeared at the top of a file, preceded
		only by blank lines and other line comments and with a blank line
		following the comment, to separate it from the package documentation.
		Unlike build constraints, this comment is only recognized in non-test
		Go source files.

		The minimal source code for a binary-only package was therefore:

		//go:binary-only-package

		package mypkg

		The source code could include additional Go code. That code was never
		compiled but would be processed by tools like godoc and might be useful
		as end-user documentation.

		"go build" and other commands no longer support binary-only-packages.
		Import and ImportDir will still set the BinaryOnly flag in packages
		containing these comments for use in tools and error messages.

	      gc.go
	      read.go
	      syslist.go
	      zcgo.go


Package-Level Type Names (total 9, in which 5 are exported)


	/* sort exporteds by:  |  */
	
		A Context specifies the supporting context for a build.

		
			
				The build, tool, and release tags specify build constraints
				that should be considered satisfied when processing +build lines.
				Clients creating a new context may customize BuildTags, which
				defaults to empty, but it is usually an error to customize ToolTags or ReleaseTags.
				ToolTags defaults to build tags appropriate to the current Go toolchain configuration.
				ReleaseTags defaults to the list of Go releases the current release is compatible with.
				BuildTags is not set for the Default build Context.
				In addition to the BuildTags, ToolTags, and ReleaseTags, build constraints
				consider the values of GOARCH and GOOS as satisfied tags.
				The last element in ReleaseTags is assumed to be the current release.

			
				// whether cgo files are included

			
				// compiler to assume when computing target paths

			
				Dir is the caller's working directory, or the empty string to use
				the current directory of the running process. In module mode, this is used
				to locate the main module.

				If Dir is non-empty, directories passed to Import and ImportDir must
				be absolute.

			
				// target architecture

			
				// target operating system

			
				// Go path

			
				// Go root

			
				HasSubdir reports whether dir is lexically a subdirectory of
				root, perhaps multiple levels below. It does not try to check
				whether dir exists.
				If so, HasSubdir sets rel to a slash-separated path that
				can be joined to root to produce a path equivalent to dir.
				If HasSubdir is nil, Import uses an implementation built on
				filepath.EvalSymlinks.

			
				The install suffix specifies a suffix to use in the name of the installation
				directory. By default it is empty, but custom builds that need to keep
				their outputs separate can set InstallSuffix to do so. For example, when
				using the race detector, the go command uses InstallSuffix = "race", so
				that on a Linux/386 system, packages are written to a directory named
				"linux_386_race" instead of the usual "linux_386".

			
				IsAbsPath reports whether path is an absolute path.
				If IsAbsPath is nil, Import uses filepath.IsAbs.

			
				IsDir reports whether the path names a directory.
				If IsDir is nil, Import calls os.Stat and uses the result's IsDir method.

			
				JoinPath joins the sequence of path fragments into a single path.
				If JoinPath is nil, Import uses filepath.Join.

			
				OpenFile opens a file (not a directory) for reading.
				If OpenFile is nil, Import uses os.Open.

			
				ReadDir returns a slice of fs.FileInfo, sorted by Name,
				describing the content of the named directory.
				If ReadDir is nil, Import uses ioutil.ReadDir.

			ReleaseTags []string
			
				SplitPathList splits the path list into a slice of individual paths.
				If SplitPathList is nil, Import uses filepath.SplitList.

			ToolTags []string
			
				// use files regardless of +build lines, file names

		
			
				Import returns details about the Go package named by the import path,
				interpreting local import paths relative to the srcDir directory.
				If the path is a local import path naming a package that can be imported
				using a standard import path, the returned package will set p.ImportPath
				to that path.

				In the directory containing the package, .go, .c, .h, and .s files are
				considered part of the package except for:

					- .go files in package documentation
					- files starting with _ or . (likely editor temporary files)
					- files with build constraints not satisfied by the context

				If an error occurs, Import returns a non-nil error and a non-nil
				*Package containing partial information.

			
				ImportDir is like Import but processes the Go package found in
				the named directory.

			
				MatchFile reports whether the file with the given name in the given directory
				matches the context and would be included in a Package created by ImportDir
				of that directory.

				MatchFile considers the name of the file and may use ctxt.OpenFile to
				read some or all of the file's content.

			
				SrcDirs returns a list of package source root directories.
				It draws from the current Go root and Go path but omits directories
				that do not exist.

			
		
			
		
			
		
			  var Default


	
		An ImportMode controls the behavior of the Import method.

		
			func Import(path, srcDir string, mode ImportMode) (*Package, error)
			func ImportDir(dir string, mode ImportMode) (*Package, error)
			func (*Context).Import(path string, srcDir string, mode ImportMode) (*Package, error)
			func (*Context).ImportDir(dir string, mode ImportMode) (*Package, error)
			
		
			const AllowBinary
			const FindOnly
			const IgnoreVendor
			const ImportComment


	
		MultiplePackageError describes a directory containing
		multiple buildable Go source files for multiple packages.

		
			
				// directory containing files

			
				// corresponding files: Files[i] declares package Packages[i]

			
				// package names found

		
			(*MultiplePackageError) Error() string
		
			*MultiplePackageError : error


	
		NoGoError is the error used by Import to describe a directory
		containing no buildable Go source files. (It may still contain
		test files, files hidden by build tags, and so on.)

		
			Dir string
		
			(*NoGoError) Error() string
		
			*NoGoError : error


	
		A Package describes the Go package found in a directory.

		
			
				// tags that can influence file selection in this directory

			
				// command install directory ("" if unknown)

			
				// cannot be rebuilt from source (has //go:binary-only-package comment)

			
				// .c source files

			
				// .cc, .cpp and .cxx source files

			
				Cgo directives
				// Cgo CFLAGS directives

			
				// Cgo CPPFLAGS directives

			
				// Cgo CXXFLAGS directives

			
				// Cgo FFLAGS directives

			
				// .go source files that import "C"

			
				// Cgo LDFLAGS directives

			
				// Cgo pkg-config directives

			
				// this directory shadows Dir in $GOPATH

			
				// directory containing package sources

			
				// documentation synopsis

			
				// line information for EmbedPatterns

			
				//go:embed patterns found in Go source files
				For example, if a source file says
					//go:embed a* b.c
				then the list will contain those two strings as separate entries.
				(See package embed for more details about //go:embed.)
				// patterns from GoFiles, CgoFiles

			
				// .f, .F, .for and .f90 Fortran source files

			
				Source files
				// .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)

			
				// package found in Go root

			
				// .h, .hh, .hpp and .hxx source files

			
				// .go source files ignored for this build (including ignored _test.go files)

			
				// non-.go source files ignored for this build

			
				// path in import comment on package statement

			
				// import path of package ("" if unknown)

			
				// line information for Imports

			
				Dependency information
				// import paths from GoFiles, CgoFiles

			
				// .go source files with detected problems (parse error, wrong package name, and so on)

			
				// .m (Objective-C) source files

			
				// package name

			
				// installed .a file

			
				// package install root directory ("" if unknown)

			
				// architecture dependent install root directory ("" if unknown)

			
				// root of Go tree where this package lives

			
				// .s source files

			
				// package source root directory ("" if unknown)

			
				// .swigcxx files

			
				// .swig files

			
				// .syso system object files to add to archive

			
				// line information for TestEmbedPatterns

			
				// patterns from TestGoFiles

			
				Test information
				// _test.go files in package

			
				// line information for TestImports

			
				// import paths from TestGoFiles

			
				// line information for XTestEmbedPatternPos

			
				// patterns from XTestGoFiles

			
				// _test.go files outside package

			
				// line information for XTestImports

			
				// import paths from XTestGoFiles

		
			
				IsCommand reports whether the package is considered a
				command to be installed (not just a library).
				Packages named "main" are treated as commands.

		
			func Import(path, srcDir string, mode ImportMode) (*Package, error)
			func ImportDir(dir string, mode ImportMode) (*Package, error)
			func (*Context).Import(path string, srcDir string, mode ImportMode) (*Package, error)
			func (*Context).ImportDir(dir string, mode ImportMode) (*Package, error)
		
			
		
			


	


Package-Level Functions (total 29, in which 4 are exported)


	
		ArchChar returns "?" and an error.
		In earlier versions of Go, the returned string was used to derive
		the compiler and linker tool names, the default object file suffix,
		and the default linker output name. As of Go 1.5, those strings
		no longer vary by architecture; they are compile, link, .o, and a.out, respectively.


	
		Import is shorthand for Default.Import.


	
		ImportDir is shorthand for Default.ImportDir.


	
		IsLocalImport reports whether the import path is
		a local import path, like ".", "..", "./foo", or "../foo".


	


Package-Level Variables (total 25, in which 2 are exported)


	
		Default is the default Context for builds.
		It uses the GOARCH, GOOS, GOROOT, and GOPATH environment variables
		if set, or else the compiled code's GOARCH, GOOS, and GOROOT.


	
		ToolDir is the directory containing build tools.


	


Package-Level Constants (total 8, in which 4 are exported)


	
		If AllowBinary is set, Import can be satisfied by a compiled
		package object without corresponding sources.

		Deprecated:
		The supported way to create a compiled-only package is to
		write source code containing a //go:binary-only-package comment at
		the top of the file. Such a package will be recognized
		regardless of this flag setting (because it has source code)
		and will have BinaryOnly set to true in the returned Package.


	
		If FindOnly is set, Import stops after locating the directory
		that should contain the sources for a package. It does not
		read any files in the directory.


	
		By default, Import searches vendor directories
		that apply in the given source directory before searching
		the GOROOT and GOPATH roots.
		If an Import finds and returns a package using a vendor
		directory, the resulting ImportPath is the complete path
		to the package, including the path elements leading up
		to and including "vendor".
		For example, if Import("y", "x/subdir", 0) finds
		"x/vendor/y", the returned package's ImportPath is "x/vendor/y",
		not plain "y".
		See golang.org/s/go15vendor for more information.

		Setting IgnoreVendor ignores vendor directories.

		In contrast to the package's ImportPath,
		the returned package's Imports, TestImports, and XTestImports
		are always the exact import paths from the source files:
		Import makes no attempt to resolve or check those paths.


	
		If ImportComment is set, parse import comments on package statements.
		Import returns an error if it finds a comment it cannot understand
		or finds conflicting comments in multiple source files.
		See golang.org/s/go14customimport for more information.