github.com/riscv/riscv-go@v0.0.0-20200123204226-124ebd6fcc8e/src/cmd/go/alldocs.go (about)

     1  // Copyright 2011 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // DO NOT EDIT THIS FILE. GENERATED BY mkalldocs.sh.
     6  // Edit the documentation in other files and rerun mkalldocs.sh to generate this one.
     7  
     8  // Go is a tool for managing Go source code.
     9  //
    10  // Usage:
    11  //
    12  // 	go command [arguments]
    13  //
    14  // The commands are:
    15  //
    16  // 	build       compile packages and dependencies
    17  // 	clean       remove object files
    18  // 	doc         show documentation for package or symbol
    19  // 	env         print Go environment information
    20  // 	bug         start a bug report
    21  // 	fix         run go tool fix on packages
    22  // 	fmt         run gofmt on package sources
    23  // 	generate    generate Go files by processing source
    24  // 	get         download and install packages and dependencies
    25  // 	install     compile and install packages and dependencies
    26  // 	list        list packages
    27  // 	run         compile and run Go program
    28  // 	test        test packages
    29  // 	tool        run specified go tool
    30  // 	version     print Go version
    31  // 	vet         run go tool vet on packages
    32  //
    33  // Use "go help [command]" for more information about a command.
    34  //
    35  // Additional help topics:
    36  //
    37  // 	c           calling between Go and C
    38  // 	buildmode   description of build modes
    39  // 	filetype    file types
    40  // 	gopath      GOPATH environment variable
    41  // 	environment environment variables
    42  // 	importpath  import path syntax
    43  // 	packages    description of package lists
    44  // 	testflag    description of testing flags
    45  // 	testfunc    description of testing functions
    46  //
    47  // Use "go help [topic]" for more information about that topic.
    48  //
    49  //
    50  // Compile packages and dependencies
    51  //
    52  // Usage:
    53  //
    54  // 	go build [-o output] [-i] [build flags] [packages]
    55  //
    56  // Build compiles the packages named by the import paths,
    57  // along with their dependencies, but it does not install the results.
    58  //
    59  // If the arguments to build are a list of .go files, build treats
    60  // them as a list of source files specifying a single package.
    61  //
    62  // When compiling a single main package, build writes
    63  // the resulting executable to an output file named after
    64  // the first source file ('go build ed.go rx.go' writes 'ed' or 'ed.exe')
    65  // or the source code directory ('go build unix/sam' writes 'sam' or 'sam.exe').
    66  // The '.exe' suffix is added when writing a Windows executable.
    67  //
    68  // When compiling multiple packages or a single non-main package,
    69  // build compiles the packages but discards the resulting object,
    70  // serving only as a check that the packages can be built.
    71  //
    72  // When compiling packages, build ignores files that end in '_test.go'.
    73  //
    74  // The -o flag, only allowed when compiling a single package,
    75  // forces build to write the resulting executable or object
    76  // to the named output file, instead of the default behavior described
    77  // in the last two paragraphs.
    78  //
    79  // The -i flag installs the packages that are dependencies of the target.
    80  //
    81  // The build flags are shared by the build, clean, get, install, list, run,
    82  // and test commands:
    83  //
    84  // 	-a
    85  // 		force rebuilding of packages that are already up-to-date.
    86  // 	-n
    87  // 		print the commands but do not run them.
    88  // 	-p n
    89  // 		the number of programs, such as build commands or
    90  // 		test binaries, that can be run in parallel.
    91  // 		The default is the number of CPUs available.
    92  // 	-race
    93  // 		enable data race detection.
    94  // 		Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64.
    95  // 	-msan
    96  // 		enable interoperation with memory sanitizer.
    97  // 		Supported only on linux/amd64,
    98  // 		and only with Clang/LLVM as the host C compiler.
    99  // 	-v
   100  // 		print the names of packages as they are compiled.
   101  // 	-work
   102  // 		print the name of the temporary work directory and
   103  // 		do not delete it when exiting.
   104  // 	-x
   105  // 		print the commands.
   106  //
   107  // 	-asmflags 'flag list'
   108  // 		arguments to pass on each go tool asm invocation.
   109  // 	-buildmode mode
   110  // 		build mode to use. See 'go help buildmode' for more.
   111  // 	-compiler name
   112  // 		name of compiler to use, as in runtime.Compiler (gccgo or gc).
   113  // 	-gccgoflags 'arg list'
   114  // 		arguments to pass on each gccgo compiler/linker invocation.
   115  // 	-gcflags 'arg list'
   116  // 		arguments to pass on each go tool compile invocation.
   117  // 	-installsuffix suffix
   118  // 		a suffix to use in the name of the package installation directory,
   119  // 		in order to keep output separate from default builds.
   120  // 		If using the -race flag, the install suffix is automatically set to race
   121  // 		or, if set explicitly, has _race appended to it.  Likewise for the -msan
   122  // 		flag.  Using a -buildmode option that requires non-default compile flags
   123  // 		has a similar effect.
   124  // 	-ldflags 'flag list'
   125  // 		arguments to pass on each go tool link invocation.
   126  // 	-linkshared
   127  // 		link against shared libraries previously created with
   128  // 		-buildmode=shared.
   129  // 	-pkgdir dir
   130  // 		install and load all packages from dir instead of the usual locations.
   131  // 		For example, when building with a non-standard configuration,
   132  // 		use -pkgdir to keep generated packages in a separate location.
   133  // 	-tags 'tag list'
   134  // 		a list of build tags to consider satisfied during the build.
   135  // 		For more information about build tags, see the description of
   136  // 		build constraints in the documentation for the go/build package.
   137  // 	-toolexec 'cmd args'
   138  // 		a program to use to invoke toolchain programs like vet and asm.
   139  // 		For example, instead of running asm, the go command will run
   140  // 		'cmd args /path/to/asm <arguments for asm>'.
   141  //
   142  // The list flags accept a space-separated list of strings. To embed spaces
   143  // in an element in the list, surround it with either single or double quotes.
   144  //
   145  // For more about specifying packages, see 'go help packages'.
   146  // For more about where packages and binaries are installed,
   147  // run 'go help gopath'.
   148  // For more about calling between Go and C/C++, run 'go help c'.
   149  //
   150  // Note: Build adheres to certain conventions such as those described
   151  // by 'go help gopath'. Not all projects can follow these conventions,
   152  // however. Installations that have their own conventions or that use
   153  // a separate software build system may choose to use lower-level
   154  // invocations such as 'go tool compile' and 'go tool link' to avoid
   155  // some of the overheads and design decisions of the build tool.
   156  //
   157  // See also: go install, go get, go clean.
   158  //
   159  //
   160  // Remove object files
   161  //
   162  // Usage:
   163  //
   164  // 	go clean [-i] [-r] [-n] [-x] [build flags] [packages]
   165  //
   166  // Clean removes object files from package source directories.
   167  // The go command builds most objects in a temporary directory,
   168  // so go clean is mainly concerned with object files left by other
   169  // tools or by manual invocations of go build.
   170  //
   171  // Specifically, clean removes the following files from each of the
   172  // source directories corresponding to the import paths:
   173  //
   174  // 	_obj/            old object directory, left from Makefiles
   175  // 	_test/           old test directory, left from Makefiles
   176  // 	_testmain.go     old gotest file, left from Makefiles
   177  // 	test.out         old test log, left from Makefiles
   178  // 	build.out        old test log, left from Makefiles
   179  // 	*.[568ao]        object files, left from Makefiles
   180  //
   181  // 	DIR(.exe)        from go build
   182  // 	DIR.test(.exe)   from go test -c
   183  // 	MAINFILE(.exe)   from go build MAINFILE.go
   184  // 	*.so             from SWIG
   185  //
   186  // In the list, DIR represents the final path element of the
   187  // directory, and MAINFILE is the base name of any Go source
   188  // file in the directory that is not included when building
   189  // the package.
   190  //
   191  // The -i flag causes clean to remove the corresponding installed
   192  // archive or binary (what 'go install' would create).
   193  //
   194  // The -n flag causes clean to print the remove commands it would execute,
   195  // but not run them.
   196  //
   197  // The -r flag causes clean to be applied recursively to all the
   198  // dependencies of the packages named by the import paths.
   199  //
   200  // The -x flag causes clean to print remove commands as it executes them.
   201  //
   202  // For more about build flags, see 'go help build'.
   203  //
   204  // For more about specifying packages, see 'go help packages'.
   205  //
   206  //
   207  // Show documentation for package or symbol
   208  //
   209  // Usage:
   210  //
   211  // 	go doc [-u] [-c] [package|[package.]symbol[.method]]
   212  //
   213  // Doc prints the documentation comments associated with the item identified by its
   214  // arguments (a package, const, func, type, var, or method) followed by a one-line
   215  // summary of each of the first-level items "under" that item (package-level
   216  // declarations for a package, methods for a type, etc.).
   217  //
   218  // Doc accepts zero, one, or two arguments.
   219  //
   220  // Given no arguments, that is, when run as
   221  //
   222  // 	go doc
   223  //
   224  // it prints the package documentation for the package in the current directory.
   225  // If the package is a command (package main), the exported symbols of the package
   226  // are elided from the presentation unless the -cmd flag is provided.
   227  //
   228  // When run with one argument, the argument is treated as a Go-syntax-like
   229  // representation of the item to be documented. What the argument selects depends
   230  // on what is installed in GOROOT and GOPATH, as well as the form of the argument,
   231  // which is schematically one of these:
   232  //
   233  // 	go doc <pkg>
   234  // 	go doc <sym>[.<method>]
   235  // 	go doc [<pkg>.]<sym>[.<method>]
   236  // 	go doc [<pkg>.][<sym>.]<method>
   237  //
   238  // The first item in this list matched by the argument is the one whose documentation
   239  // is printed. (See the examples below.) However, if the argument starts with a capital
   240  // letter it is assumed to identify a symbol or method in the current directory.
   241  //
   242  // For packages, the order of scanning is determined lexically in breadth-first order.
   243  // That is, the package presented is the one that matches the search and is nearest
   244  // the root and lexically first at its level of the hierarchy.  The GOROOT tree is
   245  // always scanned in its entirety before GOPATH.
   246  //
   247  // If there is no package specified or matched, the package in the current
   248  // directory is selected, so "go doc Foo" shows the documentation for symbol Foo in
   249  // the current package.
   250  //
   251  // The package path must be either a qualified path or a proper suffix of a
   252  // path. The go tool's usual package mechanism does not apply: package path
   253  // elements like . and ... are not implemented by go doc.
   254  //
   255  // When run with two arguments, the first must be a full package path (not just a
   256  // suffix), and the second is a symbol or symbol and method; this is similar to the
   257  // syntax accepted by godoc:
   258  //
   259  // 	go doc <pkg> <sym>[.<method>]
   260  //
   261  // In all forms, when matching symbols, lower-case letters in the argument match
   262  // either case but upper-case letters match exactly. This means that there may be
   263  // multiple matches of a lower-case argument in a package if different symbols have
   264  // different cases. If this occurs, documentation for all matches is printed.
   265  //
   266  // Examples:
   267  // 	go doc
   268  // 		Show documentation for current package.
   269  // 	go doc Foo
   270  // 		Show documentation for Foo in the current package.
   271  // 		(Foo starts with a capital letter so it cannot match
   272  // 		a package path.)
   273  // 	go doc encoding/json
   274  // 		Show documentation for the encoding/json package.
   275  // 	go doc json
   276  // 		Shorthand for encoding/json.
   277  // 	go doc json.Number (or go doc json.number)
   278  // 		Show documentation and method summary for json.Number.
   279  // 	go doc json.Number.Int64 (or go doc json.number.int64)
   280  // 		Show documentation for json.Number's Int64 method.
   281  // 	go doc cmd/doc
   282  // 		Show package docs for the doc command.
   283  // 	go doc -cmd cmd/doc
   284  // 		Show package docs and exported symbols within the doc command.
   285  // 	go doc template.new
   286  // 		Show documentation for html/template's New function.
   287  // 		(html/template is lexically before text/template)
   288  // 	go doc text/template.new # One argument
   289  // 		Show documentation for text/template's New function.
   290  // 	go doc text/template new # Two arguments
   291  // 		Show documentation for text/template's New function.
   292  //
   293  // 	At least in the current tree, these invocations all print the
   294  // 	documentation for json.Decoder's Decode method:
   295  //
   296  // 	go doc json.Decoder.Decode
   297  // 	go doc json.decoder.decode
   298  // 	go doc json.decode
   299  // 	cd go/src/encoding/json; go doc decode
   300  //
   301  // Flags:
   302  // 	-c
   303  // 		Respect case when matching symbols.
   304  // 	-cmd
   305  // 		Treat a command (package main) like a regular package.
   306  // 		Otherwise package main's exported symbols are hidden
   307  // 		when showing the package's top-level documentation.
   308  // 	-u
   309  // 		Show documentation for unexported as well as exported
   310  // 		symbols and methods.
   311  //
   312  //
   313  // Print Go environment information
   314  //
   315  // Usage:
   316  //
   317  // 	go env [var ...]
   318  //
   319  // Env prints Go environment information.
   320  //
   321  // By default env prints information as a shell script
   322  // (on Windows, a batch file).  If one or more variable
   323  // names is given as arguments,  env prints the value of
   324  // each named variable on its own line.
   325  //
   326  //
   327  // Start a bug report
   328  //
   329  // Usage:
   330  //
   331  // 	go bug
   332  //
   333  // Bug opens the default browser and starts a new bug report.
   334  // The report includes useful system information.
   335  //
   336  //
   337  // Run go tool fix on packages
   338  //
   339  // Usage:
   340  //
   341  // 	go fix [packages]
   342  //
   343  // Fix runs the Go fix command on the packages named by the import paths.
   344  //
   345  // For more about fix, see 'go doc cmd/fix'.
   346  // For more about specifying packages, see 'go help packages'.
   347  //
   348  // To run fix with specific options, run 'go tool fix'.
   349  //
   350  // See also: go fmt, go vet.
   351  //
   352  //
   353  // Run gofmt on package sources
   354  //
   355  // Usage:
   356  //
   357  // 	go fmt [-n] [-x] [packages]
   358  //
   359  // Fmt runs the command 'gofmt -l -w' on the packages named
   360  // by the import paths.  It prints the names of the files that are modified.
   361  //
   362  // For more about gofmt, see 'go doc cmd/gofmt'.
   363  // For more about specifying packages, see 'go help packages'.
   364  //
   365  // The -n flag prints commands that would be executed.
   366  // The -x flag prints commands as they are executed.
   367  //
   368  // To run gofmt with specific options, run gofmt itself.
   369  //
   370  // See also: go fix, go vet.
   371  //
   372  //
   373  // Generate Go files by processing source
   374  //
   375  // Usage:
   376  //
   377  // 	go generate [-run regexp] [-n] [-v] [-x] [build flags] [file.go... | packages]
   378  //
   379  // Generate runs commands described by directives within existing
   380  // files. Those commands can run any process but the intent is to
   381  // create or update Go source files.
   382  //
   383  // Go generate is never run automatically by go build, go get, go test,
   384  // and so on. It must be run explicitly.
   385  //
   386  // Go generate scans the file for directives, which are lines of
   387  // the form,
   388  //
   389  // 	//go:generate command argument...
   390  //
   391  // (note: no leading spaces and no space in "//go") where command
   392  // is the generator to be run, corresponding to an executable file
   393  // that can be run locally. It must either be in the shell path
   394  // (gofmt), a fully qualified path (/usr/you/bin/mytool), or a
   395  // command alias, described below.
   396  //
   397  // Note that go generate does not parse the file, so lines that look
   398  // like directives in comments or multiline strings will be treated
   399  // as directives.
   400  //
   401  // The arguments to the directive are space-separated tokens or
   402  // double-quoted strings passed to the generator as individual
   403  // arguments when it is run.
   404  //
   405  // Quoted strings use Go syntax and are evaluated before execution; a
   406  // quoted string appears as a single argument to the generator.
   407  //
   408  // Go generate sets several variables when it runs the generator:
   409  //
   410  // 	$GOARCH
   411  // 		The execution architecture (arm, amd64, etc.)
   412  // 	$GOOS
   413  // 		The execution operating system (linux, windows, etc.)
   414  // 	$GOFILE
   415  // 		The base name of the file.
   416  // 	$GOLINE
   417  // 		The line number of the directive in the source file.
   418  // 	$GOPACKAGE
   419  // 		The name of the package of the file containing the directive.
   420  // 	$DOLLAR
   421  // 		A dollar sign.
   422  //
   423  // Other than variable substitution and quoted-string evaluation, no
   424  // special processing such as "globbing" is performed on the command
   425  // line.
   426  //
   427  // As a last step before running the command, any invocations of any
   428  // environment variables with alphanumeric names, such as $GOFILE or
   429  // $HOME, are expanded throughout the command line. The syntax for
   430  // variable expansion is $NAME on all operating systems.  Due to the
   431  // order of evaluation, variables are expanded even inside quoted
   432  // strings. If the variable NAME is not set, $NAME expands to the
   433  // empty string.
   434  //
   435  // A directive of the form,
   436  //
   437  // 	//go:generate -command xxx args...
   438  //
   439  // specifies, for the remainder of this source file only, that the
   440  // string xxx represents the command identified by the arguments. This
   441  // can be used to create aliases or to handle multiword generators.
   442  // For example,
   443  //
   444  // 	//go:generate -command foo go tool foo
   445  //
   446  // specifies that the command "foo" represents the generator
   447  // "go tool foo".
   448  //
   449  // Generate processes packages in the order given on the command line,
   450  // one at a time. If the command line lists .go files, they are treated
   451  // as a single package. Within a package, generate processes the
   452  // source files in a package in file name order, one at a time. Within
   453  // a source file, generate runs generators in the order they appear
   454  // in the file, one at a time.
   455  //
   456  // If any generator returns an error exit status, "go generate" skips
   457  // all further processing for that package.
   458  //
   459  // The generator is run in the package's source directory.
   460  //
   461  // Go generate accepts one specific flag:
   462  //
   463  // 	-run=""
   464  // 		if non-empty, specifies a regular expression to select
   465  // 		directives whose full original source text (excluding
   466  // 		any trailing spaces and final newline) matches the
   467  // 		expression.
   468  //
   469  // It also accepts the standard build flags including -v, -n, and -x.
   470  // The -v flag prints the names of packages and files as they are
   471  // processed.
   472  // The -n flag prints commands that would be executed.
   473  // The -x flag prints commands as they are executed.
   474  //
   475  // For more about build flags, see 'go help build'.
   476  //
   477  // For more about specifying packages, see 'go help packages'.
   478  //
   479  //
   480  // Download and install packages and dependencies
   481  //
   482  // Usage:
   483  //
   484  // 	go get [-d] [-f] [-fix] [-insecure] [-t] [-u] [build flags] [packages]
   485  //
   486  // Get downloads the packages named by the import paths, along with their
   487  // dependencies. It then installs the named packages, like 'go install'.
   488  //
   489  // The -d flag instructs get to stop after downloading the packages; that is,
   490  // it instructs get not to install the packages.
   491  //
   492  // The -f flag, valid only when -u is set, forces get -u not to verify that
   493  // each package has been checked out from the source control repository
   494  // implied by its import path. This can be useful if the source is a local fork
   495  // of the original.
   496  //
   497  // The -fix flag instructs get to run the fix tool on the downloaded packages
   498  // before resolving dependencies or building the code.
   499  //
   500  // The -insecure flag permits fetching from repositories and resolving
   501  // custom domains using insecure schemes such as HTTP. Use with caution.
   502  //
   503  // The -t flag instructs get to also download the packages required to build
   504  // the tests for the specified packages.
   505  //
   506  // The -u flag instructs get to use the network to update the named packages
   507  // and their dependencies.  By default, get uses the network to check out
   508  // missing packages but does not use it to look for updates to existing packages.
   509  //
   510  // The -v flag enables verbose progress and debug output.
   511  //
   512  // Get also accepts build flags to control the installation. See 'go help build'.
   513  //
   514  // When checking out a new package, get creates the target directory
   515  // GOPATH/src/<import-path>. If the GOPATH contains multiple entries,
   516  // get uses the first one. For more details see: 'go help gopath'.
   517  //
   518  // When checking out or updating a package, get looks for a branch or tag
   519  // that matches the locally installed version of Go. The most important
   520  // rule is that if the local installation is running version "go1", get
   521  // searches for a branch or tag named "go1". If no such version exists it
   522  // retrieves the most recent version of the package.
   523  //
   524  // When go get checks out or updates a Git repository,
   525  // it also updates any git submodules referenced by the repository.
   526  //
   527  // Get never checks out or updates code stored in vendor directories.
   528  //
   529  // For more about specifying packages, see 'go help packages'.
   530  //
   531  // For more about how 'go get' finds source code to
   532  // download, see 'go help importpath'.
   533  //
   534  // See also: go build, go install, go clean.
   535  //
   536  //
   537  // Compile and install packages and dependencies
   538  //
   539  // Usage:
   540  //
   541  // 	go install [build flags] [packages]
   542  //
   543  // Install compiles and installs the packages named by the import paths,
   544  // along with their dependencies.
   545  //
   546  // For more about the build flags, see 'go help build'.
   547  // For more about specifying packages, see 'go help packages'.
   548  //
   549  // See also: go build, go get, go clean.
   550  //
   551  //
   552  // List packages
   553  //
   554  // Usage:
   555  //
   556  // 	go list [-e] [-f format] [-json] [build flags] [packages]
   557  //
   558  // List lists the packages named by the import paths, one per line.
   559  //
   560  // The default output shows the package import path:
   561  //
   562  //     bytes
   563  //     encoding/json
   564  //     github.com/gorilla/mux
   565  //     golang.org/x/net/html
   566  //
   567  // The -f flag specifies an alternate format for the list, using the
   568  // syntax of package template.  The default output is equivalent to -f
   569  // '{{.ImportPath}}'. The struct being passed to the template is:
   570  //
   571  //     type Package struct {
   572  //         Dir           string // directory containing package sources
   573  //         ImportPath    string // import path of package in dir
   574  //         ImportComment string // path in import comment on package statement
   575  //         Name          string // package name
   576  //         Doc           string // package documentation string
   577  //         Target        string // install path
   578  //         Shlib         string // the shared library that contains this package (only set when -linkshared)
   579  //         Goroot        bool   // is this package in the Go root?
   580  //         Standard      bool   // is this package part of the standard Go library?
   581  //         Stale         bool   // would 'go install' do anything for this package?
   582  //         StaleReason   string // explanation for Stale==true
   583  //         Root          string // Go root or Go path dir containing this package
   584  //         ConflictDir   string // this directory shadows Dir in $GOPATH
   585  //         BinaryOnly    bool   // binary-only package: cannot be recompiled from sources
   586  //
   587  //         // Source files
   588  //         GoFiles        []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
   589  //         CgoFiles       []string // .go sources files that import "C"
   590  //         IgnoredGoFiles []string // .go sources ignored due to build constraints
   591  //         CFiles         []string // .c source files
   592  //         CXXFiles       []string // .cc, .cxx and .cpp source files
   593  //         MFiles         []string // .m source files
   594  //         HFiles         []string // .h, .hh, .hpp and .hxx source files
   595  //         FFiles         []string // .f, .F, .for and .f90 Fortran source files
   596  //         SFiles         []string // .s source files
   597  //         SwigFiles      []string // .swig files
   598  //         SwigCXXFiles   []string // .swigcxx files
   599  //         SysoFiles      []string // .syso object files to add to archive
   600  //         TestGoFiles    []string // _test.go files in package
   601  //         XTestGoFiles   []string // _test.go files outside package
   602  //
   603  //         // Cgo directives
   604  //         CgoCFLAGS    []string // cgo: flags for C compiler
   605  //         CgoCPPFLAGS  []string // cgo: flags for C preprocessor
   606  //         CgoCXXFLAGS  []string // cgo: flags for C++ compiler
   607  //         CgoFFLAGS    []string // cgo: flags for Fortran compiler
   608  //         CgoLDFLAGS   []string // cgo: flags for linker
   609  //         CgoPkgConfig []string // cgo: pkg-config names
   610  //
   611  //         // Dependency information
   612  //         Imports      []string // import paths used by this package
   613  //         Deps         []string // all (recursively) imported dependencies
   614  //         TestImports  []string // imports from TestGoFiles
   615  //         XTestImports []string // imports from XTestGoFiles
   616  //
   617  //         // Error information
   618  //         Incomplete bool            // this package or a dependency has an error
   619  //         Error      *PackageError   // error loading package
   620  //         DepsErrors []*PackageError // errors loading dependencies
   621  //     }
   622  //
   623  // Packages stored in vendor directories report an ImportPath that includes the
   624  // path to the vendor directory (for example, "d/vendor/p" instead of "p"),
   625  // so that the ImportPath uniquely identifies a given copy of a package.
   626  // The Imports, Deps, TestImports, and XTestImports lists also contain these
   627  // expanded imports paths. See golang.org/s/go15vendor for more about vendoring.
   628  //
   629  // The error information, if any, is
   630  //
   631  //     type PackageError struct {
   632  //         ImportStack   []string // shortest path from package named on command line to this one
   633  //         Pos           string   // position of error (if present, file:line:col)
   634  //         Err           string   // the error itself
   635  //     }
   636  //
   637  // The template function "join" calls strings.Join.
   638  //
   639  // The template function "context" returns the build context, defined as:
   640  //
   641  // 	type Context struct {
   642  // 		GOARCH        string   // target architecture
   643  // 		GOOS          string   // target operating system
   644  // 		GOROOT        string   // Go root
   645  // 		GOPATH        string   // Go path
   646  // 		CgoEnabled    bool     // whether cgo can be used
   647  // 		UseAllFiles   bool     // use files regardless of +build lines, file names
   648  // 		Compiler      string   // compiler to assume when computing target paths
   649  // 		BuildTags     []string // build constraints to match in +build lines
   650  // 		ReleaseTags   []string // releases the current release is compatible with
   651  // 		InstallSuffix string   // suffix to use in the name of the install dir
   652  // 	}
   653  //
   654  // For more information about the meaning of these fields see the documentation
   655  // for the go/build package's Context type.
   656  //
   657  // The -json flag causes the package data to be printed in JSON format
   658  // instead of using the template format.
   659  //
   660  // The -e flag changes the handling of erroneous packages, those that
   661  // cannot be found or are malformed.  By default, the list command
   662  // prints an error to standard error for each erroneous package and
   663  // omits the packages from consideration during the usual printing.
   664  // With the -e flag, the list command never prints errors to standard
   665  // error and instead processes the erroneous packages with the usual
   666  // printing.  Erroneous packages will have a non-empty ImportPath and
   667  // a non-nil Error field; other information may or may not be missing
   668  // (zeroed).
   669  //
   670  // For more about build flags, see 'go help build'.
   671  //
   672  // For more about specifying packages, see 'go help packages'.
   673  //
   674  //
   675  // Compile and run Go program
   676  //
   677  // Usage:
   678  //
   679  // 	go run [build flags] [-exec xprog] gofiles... [arguments...]
   680  //
   681  // Run compiles and runs the main package comprising the named Go source files.
   682  // A Go source file is defined to be a file ending in a literal ".go" suffix.
   683  //
   684  // By default, 'go run' runs the compiled binary directly: 'a.out arguments...'.
   685  // If the -exec flag is given, 'go run' invokes the binary using xprog:
   686  // 	'xprog a.out arguments...'.
   687  // If the -exec flag is not given, GOOS or GOARCH is different from the system
   688  // default, and a program named go_$GOOS_$GOARCH_exec can be found
   689  // on the current search path, 'go run' invokes the binary using that program,
   690  // for example 'go_nacl_386_exec a.out arguments...'. This allows execution of
   691  // cross-compiled programs when a simulator or other execution method is
   692  // available.
   693  //
   694  // For more about build flags, see 'go help build'.
   695  //
   696  // See also: go build.
   697  //
   698  //
   699  // Test packages
   700  //
   701  // Usage:
   702  //
   703  // 	go test [build/test flags] [packages] [build/test flags & test binary flags]
   704  //
   705  // 'Go test' automates testing the packages named by the import paths.
   706  // It prints a summary of the test results in the format:
   707  //
   708  // 	ok   archive/tar   0.011s
   709  // 	FAIL archive/zip   0.022s
   710  // 	ok   compress/gzip 0.033s
   711  // 	...
   712  //
   713  // followed by detailed output for each failed package.
   714  //
   715  // 'Go test' recompiles each package along with any files with names matching
   716  // the file pattern "*_test.go".
   717  // Files whose names begin with "_" (including "_test.go") or "." are ignored.
   718  // These additional files can contain test functions, benchmark functions, and
   719  // example functions.  See 'go help testfunc' for more.
   720  // Each listed package causes the execution of a separate test binary.
   721  //
   722  // Test files that declare a package with the suffix "_test" will be compiled as a
   723  // separate package, and then linked and run with the main test binary.
   724  //
   725  // The go tool will ignore a directory named "testdata", making it available
   726  // to hold ancillary data needed by the tests.
   727  //
   728  // By default, go test needs no arguments.  It compiles and tests the package
   729  // with source in the current directory, including tests, and runs the tests.
   730  //
   731  // The package is built in a temporary directory so it does not interfere with the
   732  // non-test installation.
   733  //
   734  // In addition to the build flags, the flags handled by 'go test' itself are:
   735  //
   736  // 	-args
   737  // 	    Pass the remainder of the command line (everything after -args)
   738  // 	    to the test binary, uninterpreted and unchanged.
   739  // 	    Because this flag consumes the remainder of the command line,
   740  // 	    the package list (if present) must appear before this flag.
   741  //
   742  // 	-c
   743  // 	    Compile the test binary to pkg.test but do not run it
   744  // 	    (where pkg is the last element of the package's import path).
   745  // 	    The file name can be changed with the -o flag.
   746  //
   747  // 	-exec xprog
   748  // 	    Run the test binary using xprog. The behavior is the same as
   749  // 	    in 'go run'. See 'go help run' for details.
   750  //
   751  // 	-i
   752  // 	    Install packages that are dependencies of the test.
   753  // 	    Do not run the test.
   754  //
   755  // 	-o file
   756  // 	    Compile the test binary to the named file.
   757  // 	    The test still runs (unless -c or -i is specified).
   758  //
   759  // The test binary also accepts flags that control execution of the test; these
   760  // flags are also accessible by 'go test'. See 'go help testflag' for details.
   761  //
   762  // For more about build flags, see 'go help build'.
   763  // For more about specifying packages, see 'go help packages'.
   764  //
   765  // See also: go build, go vet.
   766  //
   767  //
   768  // Run specified go tool
   769  //
   770  // Usage:
   771  //
   772  // 	go tool [-n] command [args...]
   773  //
   774  // Tool runs the go tool command identified by the arguments.
   775  // With no arguments it prints the list of known tools.
   776  //
   777  // The -n flag causes tool to print the command that would be
   778  // executed but not execute it.
   779  //
   780  // For more about each tool command, see 'go tool command -h'.
   781  //
   782  //
   783  // Print Go version
   784  //
   785  // Usage:
   786  //
   787  // 	go version
   788  //
   789  // Version prints the Go version, as reported by runtime.Version.
   790  //
   791  //
   792  // Run go tool vet on packages
   793  //
   794  // Usage:
   795  //
   796  // 	go vet [-n] [-x] [build flags] [packages]
   797  //
   798  // Vet runs the Go vet command on the packages named by the import paths.
   799  //
   800  // For more about vet, see 'go doc cmd/vet'.
   801  // For more about specifying packages, see 'go help packages'.
   802  //
   803  // To run the vet tool with specific options, run 'go tool vet'.
   804  //
   805  // The -n flag prints commands that would be executed.
   806  // The -x flag prints commands as they are executed.
   807  //
   808  // For more about build flags, see 'go help build'.
   809  //
   810  // See also: go fmt, go fix.
   811  //
   812  //
   813  // Calling between Go and C
   814  //
   815  // There are two different ways to call between Go and C/C++ code.
   816  //
   817  // The first is the cgo tool, which is part of the Go distribution.  For
   818  // information on how to use it see the cgo documentation (go doc cmd/cgo).
   819  //
   820  // The second is the SWIG program, which is a general tool for
   821  // interfacing between languages.  For information on SWIG see
   822  // http://swig.org/.  When running go build, any file with a .swig
   823  // extension will be passed to SWIG.  Any file with a .swigcxx extension
   824  // will be passed to SWIG with the -c++ option.
   825  //
   826  // When either cgo or SWIG is used, go build will pass any .c, .m, .s,
   827  // or .S files to the C compiler, and any .cc, .cpp, .cxx files to the C++
   828  // compiler.  The CC or CXX environment variables may be set to determine
   829  // the C or C++ compiler, respectively, to use.
   830  //
   831  //
   832  // Description of build modes
   833  //
   834  // The 'go build' and 'go install' commands take a -buildmode argument which
   835  // indicates which kind of object file is to be built. Currently supported values
   836  // are:
   837  //
   838  // 	-buildmode=archive
   839  // 		Build the listed non-main packages into .a files. Packages named
   840  // 		main are ignored.
   841  //
   842  // 	-buildmode=c-archive
   843  // 		Build the listed main package, plus all packages it imports,
   844  // 		into a C archive file. The only callable symbols will be those
   845  // 		functions exported using a cgo //export comment. Requires
   846  // 		exactly one main package to be listed.
   847  //
   848  // 	-buildmode=c-shared
   849  // 		Build the listed main packages, plus all packages that they
   850  // 		import, into C shared libraries. The only callable symbols will
   851  // 		be those functions exported using a cgo //export comment.
   852  // 		Non-main packages are ignored.
   853  //
   854  // 	-buildmode=default
   855  // 		Listed main packages are built into executables and listed
   856  // 		non-main packages are built into .a files (the default
   857  // 		behavior).
   858  //
   859  // 	-buildmode=shared
   860  // 		Combine all the listed non-main packages into a single shared
   861  // 		library that will be used when building with the -linkshared
   862  // 		option. Packages named main are ignored.
   863  //
   864  // 	-buildmode=exe
   865  // 		Build the listed main packages and everything they import into
   866  // 		executables. Packages not named main are ignored.
   867  //
   868  // 	-buildmode=pie
   869  // 		Build the listed main packages and everything they import into
   870  // 		position independent executables (PIE). Packages not named
   871  // 		main are ignored.
   872  //
   873  // 	-buildmode=plugin
   874  // 		Build the listed main packages, plus all packages that they
   875  // 		import, into a Go plugin. Packages not named main are ignored.
   876  //
   877  //
   878  // File types
   879  //
   880  // The go command examines the contents of a restricted set of files
   881  // in each directory. It identifies which files to examine based on
   882  // the extension of the file name. These extensions are:
   883  //
   884  // 	.go
   885  // 		Go source files.
   886  // 	.c, .h
   887  // 		C source files.
   888  // 		If the package uses cgo or SWIG, these will be compiled with the
   889  // 		OS-native compiler (typically gcc); otherwise they will
   890  // 		trigger an error.
   891  // 	.cc, .cpp, .cxx, .hh, .hpp, .hxx
   892  // 		C++ source files. Only useful with cgo or SWIG, and always
   893  // 		compiled with the OS-native compiler.
   894  // 	.m
   895  // 		Objective-C source files. Only useful with cgo, and always
   896  // 		compiled with the OS-native compiler.
   897  // 	.s, .S
   898  // 		Assembler source files.
   899  // 		If the package uses cgo or SWIG, these will be assembled with the
   900  // 		OS-native assembler (typically gcc (sic)); otherwise they
   901  // 		will be assembled with the Go assembler.
   902  // 	.swig, .swigcxx
   903  // 		SWIG definition files.
   904  // 	.syso
   905  // 		System object files.
   906  //
   907  // Files of each of these types except .syso may contain build
   908  // constraints, but the go command stops scanning for build constraints
   909  // at the first item in the file that is not a blank line or //-style
   910  // line comment. See the go/build package documentation for
   911  // more details.
   912  //
   913  // Non-test Go source files can also include a //go:binary-only-package
   914  // comment, indicating that the package sources are included
   915  // for documentation only and must not be used to build the
   916  // package binary. This enables distribution of Go packages in
   917  // their compiled form alone. See the go/build package documentation
   918  // for more details.
   919  //
   920  //
   921  // GOPATH environment variable
   922  //
   923  // The Go path is used to resolve import statements.
   924  // It is implemented by and documented in the go/build package.
   925  //
   926  // The GOPATH environment variable lists places to look for Go code.
   927  // On Unix, the value is a colon-separated string.
   928  // On Windows, the value is a semicolon-separated string.
   929  // On Plan 9, the value is a list.
   930  //
   931  // If the environment variable is unset, GOPATH defaults
   932  // to a subdirectory named "go" in the user's home directory
   933  // ($HOME/go on Unix, %USERPROFILE%\go on Windows),
   934  // unless that directory holds a Go distribution.
   935  // Run "go env GOPATH" to see the current GOPATH.
   936  //
   937  // See https://golang.org/wiki/SettingGOPATH to set a custom GOPATH.
   938  //
   939  // Each directory listed in GOPATH must have a prescribed structure:
   940  //
   941  // The src directory holds source code.  The path below src
   942  // determines the import path or executable name.
   943  //
   944  // The pkg directory holds installed package objects.
   945  // As in the Go tree, each target operating system and
   946  // architecture pair has its own subdirectory of pkg
   947  // (pkg/GOOS_GOARCH).
   948  //
   949  // If DIR is a directory listed in the GOPATH, a package with
   950  // source in DIR/src/foo/bar can be imported as "foo/bar" and
   951  // has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a".
   952  //
   953  // The bin directory holds compiled commands.
   954  // Each command is named for its source directory, but only
   955  // the final element, not the entire path.  That is, the
   956  // command with source in DIR/src/foo/quux is installed into
   957  // DIR/bin/quux, not DIR/bin/foo/quux.  The "foo/" prefix is stripped
   958  // so that you can add DIR/bin to your PATH to get at the
   959  // installed commands.  If the GOBIN environment variable is
   960  // set, commands are installed to the directory it names instead
   961  // of DIR/bin. GOBIN must be an absolute path.
   962  //
   963  // Here's an example directory layout:
   964  //
   965  //     GOPATH=/home/user/go
   966  //
   967  //     /home/user/go/
   968  //         src/
   969  //             foo/
   970  //                 bar/               (go code in package bar)
   971  //                     x.go
   972  //                 quux/              (go code in package main)
   973  //                     y.go
   974  //         bin/
   975  //             quux                   (installed command)
   976  //         pkg/
   977  //             linux_amd64/
   978  //                 foo/
   979  //                     bar.a          (installed package object)
   980  //
   981  // Go searches each directory listed in GOPATH to find source code,
   982  // but new packages are always downloaded into the first directory
   983  // in the list.
   984  //
   985  // See https://golang.org/doc/code.html for an example.
   986  //
   987  // Internal Directories
   988  //
   989  // Code in or below a directory named "internal" is importable only
   990  // by code in the directory tree rooted at the parent of "internal".
   991  // Here's an extended version of the directory layout above:
   992  //
   993  //     /home/user/go/
   994  //         src/
   995  //             crash/
   996  //                 bang/              (go code in package bang)
   997  //                     b.go
   998  //             foo/                   (go code in package foo)
   999  //                 f.go
  1000  //                 bar/               (go code in package bar)
  1001  //                     x.go
  1002  //                 internal/
  1003  //                     baz/           (go code in package baz)
  1004  //                         z.go
  1005  //                 quux/              (go code in package main)
  1006  //                     y.go
  1007  //
  1008  //
  1009  // The code in z.go is imported as "foo/internal/baz", but that
  1010  // import statement can only appear in source files in the subtree
  1011  // rooted at foo. The source files foo/f.go, foo/bar/x.go, and
  1012  // foo/quux/y.go can all import "foo/internal/baz", but the source file
  1013  // crash/bang/b.go cannot.
  1014  //
  1015  // See https://golang.org/s/go14internal for details.
  1016  //
  1017  // Vendor Directories
  1018  //
  1019  // Go 1.6 includes support for using local copies of external dependencies
  1020  // to satisfy imports of those dependencies, often referred to as vendoring.
  1021  //
  1022  // Code below a directory named "vendor" is importable only
  1023  // by code in the directory tree rooted at the parent of "vendor",
  1024  // and only using an import path that omits the prefix up to and
  1025  // including the vendor element.
  1026  //
  1027  // Here's the example from the previous section,
  1028  // but with the "internal" directory renamed to "vendor"
  1029  // and a new foo/vendor/crash/bang directory added:
  1030  //
  1031  //     /home/user/go/
  1032  //         src/
  1033  //             crash/
  1034  //                 bang/              (go code in package bang)
  1035  //                     b.go
  1036  //             foo/                   (go code in package foo)
  1037  //                 f.go
  1038  //                 bar/               (go code in package bar)
  1039  //                     x.go
  1040  //                 vendor/
  1041  //                     crash/
  1042  //                         bang/      (go code in package bang)
  1043  //                             b.go
  1044  //                     baz/           (go code in package baz)
  1045  //                         z.go
  1046  //                 quux/              (go code in package main)
  1047  //                     y.go
  1048  //
  1049  // The same visibility rules apply as for internal, but the code
  1050  // in z.go is imported as "baz", not as "foo/vendor/baz".
  1051  //
  1052  // Code in vendor directories deeper in the source tree shadows
  1053  // code in higher directories. Within the subtree rooted at foo, an import
  1054  // of "crash/bang" resolves to "foo/vendor/crash/bang", not the
  1055  // top-level "crash/bang".
  1056  //
  1057  // Code in vendor directories is not subject to import path
  1058  // checking (see 'go help importpath').
  1059  //
  1060  // When 'go get' checks out or updates a git repository, it now also
  1061  // updates submodules.
  1062  //
  1063  // Vendor directories do not affect the placement of new repositories
  1064  // being checked out for the first time by 'go get': those are always
  1065  // placed in the main GOPATH, never in a vendor subtree.
  1066  //
  1067  // See https://golang.org/s/go15vendor for details.
  1068  //
  1069  //
  1070  // Environment variables
  1071  //
  1072  // The go command, and the tools it invokes, examine a few different
  1073  // environment variables. For many of these, you can see the default
  1074  // value of on your system by running 'go env NAME', where NAME is the
  1075  // name of the variable.
  1076  //
  1077  // General-purpose environment variables:
  1078  //
  1079  // 	GCCGO
  1080  // 		The gccgo command to run for 'go build -compiler=gccgo'.
  1081  // 	GOARCH
  1082  // 		The architecture, or processor, for which to compile code.
  1083  // 		Examples are amd64, 386, arm, ppc64.
  1084  // 	GOBIN
  1085  // 		The directory where 'go install' will install a command.
  1086  // 	GOOS
  1087  // 		The operating system for which to compile code.
  1088  // 		Examples are linux, darwin, windows, netbsd.
  1089  // 	GOPATH
  1090  // 		For more details see: 'go help gopath'.
  1091  // 	GORACE
  1092  // 		Options for the race detector.
  1093  // 		See https://golang.org/doc/articles/race_detector.html.
  1094  // 	GOROOT
  1095  // 		The root of the go tree.
  1096  //
  1097  // Environment variables for use with cgo:
  1098  //
  1099  // 	CC
  1100  // 		The command to use to compile C code.
  1101  // 	CGO_ENABLED
  1102  // 		Whether the cgo command is supported.  Either 0 or 1.
  1103  // 	CGO_CFLAGS
  1104  // 		Flags that cgo will pass to the compiler when compiling
  1105  // 		C code.
  1106  // 	CGO_CPPFLAGS
  1107  // 		Flags that cgo will pass to the compiler when compiling
  1108  // 		C or C++ code.
  1109  // 	CGO_CXXFLAGS
  1110  // 		Flags that cgo will pass to the compiler when compiling
  1111  // 		C++ code.
  1112  // 	CGO_FFLAGS
  1113  // 		Flags that cgo will pass to the compiler when compiling
  1114  // 		Fortran code.
  1115  // 	CGO_LDFLAGS
  1116  // 		Flags that cgo will pass to the compiler when linking.
  1117  // 	CXX
  1118  // 		The command to use to compile C++ code.
  1119  // 	PKG_CONFIG
  1120  // 		Path to pkg-config tool.
  1121  //
  1122  // Architecture-specific environment variables:
  1123  //
  1124  // 	GOARM
  1125  // 		For GOARCH=arm, the ARM architecture for which to compile.
  1126  // 		Valid values are 5, 6, 7.
  1127  // 	GO386
  1128  // 		For GOARCH=386, the floating point instruction set.
  1129  // 		Valid values are 387, sse2.
  1130  //
  1131  // Special-purpose environment variables:
  1132  //
  1133  // 	GOROOT_FINAL
  1134  // 		The root of the installed Go tree, when it is
  1135  // 		installed in a location other than where it is built.
  1136  // 		File names in stack traces are rewritten from GOROOT to
  1137  // 		GOROOT_FINAL.
  1138  // 	GO_EXTLINK_ENABLED
  1139  // 		Whether the linker should use external linking mode
  1140  // 		when using -linkmode=auto with code that uses cgo.
  1141  // 		Set to 0 to disable external linking mode, 1 to enable it.
  1142  // 	GIT_ALLOW_PROTOCOL
  1143  // 		Defined by Git. A colon-separated list of schemes that are allowed to be used
  1144  // 		with git fetch/clone. If set, any scheme not explicitly mentioned will be
  1145  // 		considered insecure by 'go get'.
  1146  //
  1147  //
  1148  // Import path syntax
  1149  //
  1150  // An import path (see 'go help packages') denotes a package stored in the local
  1151  // file system.  In general, an import path denotes either a standard package (such
  1152  // as "unicode/utf8") or a package found in one of the work spaces (For more
  1153  // details see: 'go help gopath').
  1154  //
  1155  // Relative import paths
  1156  //
  1157  // An import path beginning with ./ or ../ is called a relative path.
  1158  // The toolchain supports relative import paths as a shortcut in two ways.
  1159  //
  1160  // First, a relative path can be used as a shorthand on the command line.
  1161  // If you are working in the directory containing the code imported as
  1162  // "unicode" and want to run the tests for "unicode/utf8", you can type
  1163  // "go test ./utf8" instead of needing to specify the full path.
  1164  // Similarly, in the reverse situation, "go test .." will test "unicode" from
  1165  // the "unicode/utf8" directory. Relative patterns are also allowed, like
  1166  // "go test ./..." to test all subdirectories. See 'go help packages' for details
  1167  // on the pattern syntax.
  1168  //
  1169  // Second, if you are compiling a Go program not in a work space,
  1170  // you can use a relative path in an import statement in that program
  1171  // to refer to nearby code also not in a work space.
  1172  // This makes it easy to experiment with small multipackage programs
  1173  // outside of the usual work spaces, but such programs cannot be
  1174  // installed with "go install" (there is no work space in which to install them),
  1175  // so they are rebuilt from scratch each time they are built.
  1176  // To avoid ambiguity, Go programs cannot use relative import paths
  1177  // within a work space.
  1178  //
  1179  // Remote import paths
  1180  //
  1181  // Certain import paths also
  1182  // describe how to obtain the source code for the package using
  1183  // a revision control system.
  1184  //
  1185  // A few common code hosting sites have special syntax:
  1186  //
  1187  // 	Bitbucket (Git, Mercurial)
  1188  //
  1189  // 		import "bitbucket.org/user/project"
  1190  // 		import "bitbucket.org/user/project/sub/directory"
  1191  //
  1192  // 	GitHub (Git)
  1193  //
  1194  // 		import "github.com/user/project"
  1195  // 		import "github.com/user/project/sub/directory"
  1196  //
  1197  // 	Launchpad (Bazaar)
  1198  //
  1199  // 		import "launchpad.net/project"
  1200  // 		import "launchpad.net/project/series"
  1201  // 		import "launchpad.net/project/series/sub/directory"
  1202  //
  1203  // 		import "launchpad.net/~user/project/branch"
  1204  // 		import "launchpad.net/~user/project/branch/sub/directory"
  1205  //
  1206  // 	IBM DevOps Services (Git)
  1207  //
  1208  // 		import "hub.jazz.net/git/user/project"
  1209  // 		import "hub.jazz.net/git/user/project/sub/directory"
  1210  //
  1211  // For code hosted on other servers, import paths may either be qualified
  1212  // with the version control type, or the go tool can dynamically fetch
  1213  // the import path over https/http and discover where the code resides
  1214  // from a <meta> tag in the HTML.
  1215  //
  1216  // To declare the code location, an import path of the form
  1217  //
  1218  // 	repository.vcs/path
  1219  //
  1220  // specifies the given repository, with or without the .vcs suffix,
  1221  // using the named version control system, and then the path inside
  1222  // that repository.  The supported version control systems are:
  1223  //
  1224  // 	Bazaar      .bzr
  1225  // 	Git         .git
  1226  // 	Mercurial   .hg
  1227  // 	Subversion  .svn
  1228  //
  1229  // For example,
  1230  //
  1231  // 	import "example.org/user/foo.hg"
  1232  //
  1233  // denotes the root directory of the Mercurial repository at
  1234  // example.org/user/foo or foo.hg, and
  1235  //
  1236  // 	import "example.org/repo.git/foo/bar"
  1237  //
  1238  // denotes the foo/bar directory of the Git repository at
  1239  // example.org/repo or repo.git.
  1240  //
  1241  // When a version control system supports multiple protocols,
  1242  // each is tried in turn when downloading.  For example, a Git
  1243  // download tries https://, then git+ssh://.
  1244  //
  1245  // By default, downloads are restricted to known secure protocols
  1246  // (e.g. https, ssh). To override this setting for Git downloads, the
  1247  // GIT_ALLOW_PROTOCOL environment variable can be set (For more details see:
  1248  // 'go help environment').
  1249  //
  1250  // If the import path is not a known code hosting site and also lacks a
  1251  // version control qualifier, the go tool attempts to fetch the import
  1252  // over https/http and looks for a <meta> tag in the document's HTML
  1253  // <head>.
  1254  //
  1255  // The meta tag has the form:
  1256  //
  1257  // 	<meta name="go-import" content="import-prefix vcs repo-root">
  1258  //
  1259  // The import-prefix is the import path corresponding to the repository
  1260  // root. It must be a prefix or an exact match of the package being
  1261  // fetched with "go get". If it's not an exact match, another http
  1262  // request is made at the prefix to verify the <meta> tags match.
  1263  //
  1264  // The meta tag should appear as early in the file as possible.
  1265  // In particular, it should appear before any raw JavaScript or CSS,
  1266  // to avoid confusing the go command's restricted parser.
  1267  //
  1268  // The vcs is one of "git", "hg", "svn", etc,
  1269  //
  1270  // The repo-root is the root of the version control system
  1271  // containing a scheme and not containing a .vcs qualifier.
  1272  //
  1273  // For example,
  1274  //
  1275  // 	import "example.org/pkg/foo"
  1276  //
  1277  // will result in the following requests:
  1278  //
  1279  // 	https://example.org/pkg/foo?go-get=1 (preferred)
  1280  // 	http://example.org/pkg/foo?go-get=1  (fallback, only with -insecure)
  1281  //
  1282  // If that page contains the meta tag
  1283  //
  1284  // 	<meta name="go-import" content="example.org git https://code.org/r/p/exproj">
  1285  //
  1286  // the go tool will verify that https://example.org/?go-get=1 contains the
  1287  // same meta tag and then git clone https://code.org/r/p/exproj into
  1288  // GOPATH/src/example.org.
  1289  //
  1290  // New downloaded packages are written to the first directory listed in the GOPATH
  1291  // environment variable (For more details see: 'go help gopath').
  1292  //
  1293  // The go command attempts to download the version of the
  1294  // package appropriate for the Go release being used.
  1295  // Run 'go help get' for more.
  1296  //
  1297  // Import path checking
  1298  //
  1299  // When the custom import path feature described above redirects to a
  1300  // known code hosting site, each of the resulting packages has two possible
  1301  // import paths, using the custom domain or the known hosting site.
  1302  //
  1303  // A package statement is said to have an "import comment" if it is immediately
  1304  // followed (before the next newline) by a comment of one of these two forms:
  1305  //
  1306  // 	package math // import "path"
  1307  // 	package math /* import "path" */
  1308  //
  1309  // The go command will refuse to install a package with an import comment
  1310  // unless it is being referred to by that import path. In this way, import comments
  1311  // let package authors make sure the custom import path is used and not a
  1312  // direct path to the underlying code hosting site.
  1313  //
  1314  // Import path checking is disabled for code found within vendor trees.
  1315  // This makes it possible to copy code into alternate locations in vendor trees
  1316  // without needing to update import comments.
  1317  //
  1318  // See https://golang.org/s/go14customimport for details.
  1319  //
  1320  //
  1321  // Description of package lists
  1322  //
  1323  // Many commands apply to a set of packages:
  1324  //
  1325  // 	go action [packages]
  1326  //
  1327  // Usually, [packages] is a list of import paths.
  1328  //
  1329  // An import path that is a rooted path or that begins with
  1330  // a . or .. element is interpreted as a file system path and
  1331  // denotes the package in that directory.
  1332  //
  1333  // Otherwise, the import path P denotes the package found in
  1334  // the directory DIR/src/P for some DIR listed in the GOPATH
  1335  // environment variable (For more details see: 'go help gopath').
  1336  //
  1337  // If no import paths are given, the action applies to the
  1338  // package in the current directory.
  1339  //
  1340  // There are four reserved names for paths that should not be used
  1341  // for packages to be built with the go tool:
  1342  //
  1343  // - "main" denotes the top-level package in a stand-alone executable.
  1344  //
  1345  // - "all" expands to all package directories found in all the GOPATH
  1346  // trees. For example, 'go list all' lists all the packages on the local
  1347  // system.
  1348  //
  1349  // - "std" is like all but expands to just the packages in the standard
  1350  // Go library.
  1351  //
  1352  // - "cmd" expands to the Go repository's commands and their
  1353  // internal libraries.
  1354  //
  1355  // Import paths beginning with "cmd/" only match source code in
  1356  // the Go repository.
  1357  //
  1358  // An import path is a pattern if it includes one or more "..." wildcards,
  1359  // each of which can match any string, including the empty string and
  1360  // strings containing slashes.  Such a pattern expands to all package
  1361  // directories found in the GOPATH trees with names matching the
  1362  // patterns.  As a special case, x/... matches x as well as x's subdirectories.
  1363  // For example, net/... expands to net and packages in its subdirectories.
  1364  //
  1365  // An import path can also name a package to be downloaded from
  1366  // a remote repository.  Run 'go help importpath' for details.
  1367  //
  1368  // Every package in a program must have a unique import path.
  1369  // By convention, this is arranged by starting each path with a
  1370  // unique prefix that belongs to you.  For example, paths used
  1371  // internally at Google all begin with 'google', and paths
  1372  // denoting remote repositories begin with the path to the code,
  1373  // such as 'github.com/user/repo'.
  1374  //
  1375  // Packages in a program need not have unique package names,
  1376  // but there are two reserved package names with special meaning.
  1377  // The name main indicates a command, not a library.
  1378  // Commands are built into binaries and cannot be imported.
  1379  // The name documentation indicates documentation for
  1380  // a non-Go program in the directory. Files in package documentation
  1381  // are ignored by the go command.
  1382  //
  1383  // As a special case, if the package list is a list of .go files from a
  1384  // single directory, the command is applied to a single synthesized
  1385  // package made up of exactly those files, ignoring any build constraints
  1386  // in those files and ignoring any other files in the directory.
  1387  //
  1388  // Directory and file names that begin with "." or "_" are ignored
  1389  // by the go tool, as are directories named "testdata".
  1390  //
  1391  //
  1392  // Description of testing flags
  1393  //
  1394  // The 'go test' command takes both flags that apply to 'go test' itself
  1395  // and flags that apply to the resulting test binary.
  1396  //
  1397  // Several of the flags control profiling and write an execution profile
  1398  // suitable for "go tool pprof"; run "go tool pprof -h" for more
  1399  // information.  The --alloc_space, --alloc_objects, and --show_bytes
  1400  // options of pprof control how the information is presented.
  1401  //
  1402  // The following flags are recognized by the 'go test' command and
  1403  // control the execution of any test:
  1404  //
  1405  // 	-bench regexp
  1406  // 	    Run (sub)benchmarks matching a regular expression.
  1407  // 	    The given regular expression is split into smaller ones by
  1408  // 	    top-level '/', where each must match the corresponding part of a
  1409  // 	    benchmark's identifier.
  1410  // 	    By default, no benchmarks run. To run all benchmarks,
  1411  // 	    use '-bench .' or '-bench=.'.
  1412  //
  1413  // 	-benchtime t
  1414  // 	    Run enough iterations of each benchmark to take t, specified
  1415  // 	    as a time.Duration (for example, -benchtime 1h30s).
  1416  // 	    The default is 1 second (1s).
  1417  //
  1418  // 	-count n
  1419  // 	    Run each test and benchmark n times (default 1).
  1420  // 	    If -cpu is set, run n times for each GOMAXPROCS value.
  1421  // 	    Examples are always run once.
  1422  //
  1423  // 	-cover
  1424  // 	    Enable coverage analysis.
  1425  //
  1426  // 	-covermode set,count,atomic
  1427  // 	    Set the mode for coverage analysis for the package[s]
  1428  // 	    being tested. The default is "set" unless -race is enabled,
  1429  // 	    in which case it is "atomic".
  1430  // 	    The values:
  1431  // 		set: bool: does this statement run?
  1432  // 		count: int: how many times does this statement run?
  1433  // 		atomic: int: count, but correct in multithreaded tests;
  1434  // 			significantly more expensive.
  1435  // 	    Sets -cover.
  1436  //
  1437  // 	-coverpkg pkg1,pkg2,pkg3
  1438  // 	    Apply coverage analysis in each test to the given list of packages.
  1439  // 	    The default is for each test to analyze only the package being tested.
  1440  // 	    Packages are specified as import paths.
  1441  // 	    Sets -cover.
  1442  //
  1443  // 	-cpu 1,2,4
  1444  // 	    Specify a list of GOMAXPROCS values for which the tests or
  1445  // 	    benchmarks should be executed.  The default is the current value
  1446  // 	    of GOMAXPROCS.
  1447  //
  1448  // 	-parallel n
  1449  // 	    Allow parallel execution of test functions that call t.Parallel.
  1450  // 	    The value of this flag is the maximum number of tests to run
  1451  // 	    simultaneously; by default, it is set to the value of GOMAXPROCS.
  1452  // 	    Note that -parallel only applies within a single test binary.
  1453  // 	    The 'go test' command may run tests for different packages
  1454  // 	    in parallel as well, according to the setting of the -p flag
  1455  // 	    (see 'go help build').
  1456  //
  1457  // 	-run regexp
  1458  // 	    Run only those tests and examples matching the regular expression.
  1459  // 	    For tests the regular expression is split into smaller ones by
  1460  // 	    top-level '/', where each must match the corresponding part of a
  1461  // 	    test's identifier.
  1462  //
  1463  // 	-short
  1464  // 	    Tell long-running tests to shorten their run time.
  1465  // 	    It is off by default but set during all.bash so that installing
  1466  // 	    the Go tree can run a sanity check but not spend time running
  1467  // 	    exhaustive tests.
  1468  //
  1469  // 	-timeout t
  1470  // 	    If a test runs longer than t, panic.
  1471  // 	    The default is 10 minutes (10m).
  1472  //
  1473  // 	-v
  1474  // 	    Verbose output: log all tests as they are run. Also print all
  1475  // 	    text from Log and Logf calls even if the test succeeds.
  1476  //
  1477  // The following flags are also recognized by 'go test' and can be used to
  1478  // profile the tests during execution:
  1479  //
  1480  // 	-benchmem
  1481  // 	    Print memory allocation statistics for benchmarks.
  1482  //
  1483  // 	-blockprofile block.out
  1484  // 	    Write a goroutine blocking profile to the specified file
  1485  // 	    when all tests are complete.
  1486  // 	    Writes test binary as -c would.
  1487  //
  1488  // 	-blockprofilerate n
  1489  // 	    Control the detail provided in goroutine blocking profiles by
  1490  // 	    calling runtime.SetBlockProfileRate with n.
  1491  // 	    See 'go doc runtime.SetBlockProfileRate'.
  1492  // 	    The profiler aims to sample, on average, one blocking event every
  1493  // 	    n nanoseconds the program spends blocked.  By default,
  1494  // 	    if -test.blockprofile is set without this flag, all blocking events
  1495  // 	    are recorded, equivalent to -test.blockprofilerate=1.
  1496  //
  1497  // 	-coverprofile cover.out
  1498  // 	    Write a coverage profile to the file after all tests have passed.
  1499  // 	    Sets -cover.
  1500  //
  1501  // 	-cpuprofile cpu.out
  1502  // 	    Write a CPU profile to the specified file before exiting.
  1503  // 	    Writes test binary as -c would.
  1504  //
  1505  // 	-memprofile mem.out
  1506  // 	    Write a memory profile to the file after all tests have passed.
  1507  // 	    Writes test binary as -c would.
  1508  //
  1509  // 	-memprofilerate n
  1510  // 	    Enable more precise (and expensive) memory profiles by setting
  1511  // 	    runtime.MemProfileRate.  See 'go doc runtime.MemProfileRate'.
  1512  // 	    To profile all memory allocations, use -test.memprofilerate=1
  1513  // 	    and pass --alloc_space flag to the pprof tool.
  1514  //
  1515  // 	-mutexprofile mutex.out
  1516  // 	    Write a mutex contention profile to the specified file
  1517  // 	    when all tests are complete.
  1518  // 	    Writes test binary as -c would.
  1519  //
  1520  // 	-mutexprofilefraction n
  1521  // 	    Sample 1 in n stack traces of goroutines holding a
  1522  // 	    contended mutex.
  1523  //
  1524  // 	-outputdir directory
  1525  // 	    Place output files from profiling in the specified directory,
  1526  // 	    by default the directory in which "go test" is running.
  1527  //
  1528  // 	-trace trace.out
  1529  // 	    Write an execution trace to the specified file before exiting.
  1530  //
  1531  // Each of these flags is also recognized with an optional 'test.' prefix,
  1532  // as in -test.v. When invoking the generated test binary (the result of
  1533  // 'go test -c') directly, however, the prefix is mandatory.
  1534  //
  1535  // The 'go test' command rewrites or removes recognized flags,
  1536  // as appropriate, both before and after the optional package list,
  1537  // before invoking the test binary.
  1538  //
  1539  // For instance, the command
  1540  //
  1541  // 	go test -v -myflag testdata -cpuprofile=prof.out -x
  1542  //
  1543  // will compile the test binary and then run it as
  1544  //
  1545  // 	pkg.test -test.v -myflag testdata -test.cpuprofile=prof.out
  1546  //
  1547  // (The -x flag is removed because it applies only to the go command's
  1548  // execution, not to the test itself.)
  1549  //
  1550  // The test flags that generate profiles (other than for coverage) also
  1551  // leave the test binary in pkg.test for use when analyzing the profiles.
  1552  //
  1553  // When 'go test' runs a test binary, it does so from within the
  1554  // corresponding package's source code directory. Depending on the test,
  1555  // it may be necessary to do the same when invoking a generated test
  1556  // binary directly.
  1557  //
  1558  // The command-line package list, if present, must appear before any
  1559  // flag not known to the go test command. Continuing the example above,
  1560  // the package list would have to appear before -myflag, but could appear
  1561  // on either side of -v.
  1562  //
  1563  // To keep an argument for a test binary from being interpreted as a
  1564  // known flag or a package name, use -args (see 'go help test') which
  1565  // passes the remainder of the command line through to the test binary
  1566  // uninterpreted and unaltered.
  1567  //
  1568  // For instance, the command
  1569  //
  1570  // 	go test -v -args -x -v
  1571  //
  1572  // will compile the test binary and then run it as
  1573  //
  1574  // 	pkg.test -test.v -x -v
  1575  //
  1576  // Similarly,
  1577  //
  1578  // 	go test -args math
  1579  //
  1580  // will compile the test binary and then run it as
  1581  //
  1582  // 	pkg.test math
  1583  //
  1584  // In the first example, the -x and the second -v are passed through to the
  1585  // test binary unchanged and with no effect on the go command itself.
  1586  // In the second example, the argument math is passed through to the test
  1587  // binary, instead of being interpreted as the package list.
  1588  //
  1589  //
  1590  // Description of testing functions
  1591  //
  1592  // The 'go test' command expects to find test, benchmark, and example functions
  1593  // in the "*_test.go" files corresponding to the package under test.
  1594  //
  1595  // A test function is one named TestXXX (where XXX is any alphanumeric string
  1596  // not starting with a lower case letter) and should have the signature,
  1597  //
  1598  // 	func TestXXX(t *testing.T) { ... }
  1599  //
  1600  // A benchmark function is one named BenchmarkXXX and should have the signature,
  1601  //
  1602  // 	func BenchmarkXXX(b *testing.B) { ... }
  1603  //
  1604  // An example function is similar to a test function but, instead of using
  1605  // *testing.T to report success or failure, prints output to os.Stdout.
  1606  // If the last comment in the function starts with "Output:" then the output
  1607  // is compared exactly against the comment (see examples below). If the last
  1608  // comment begins with "Unordered output:" then the output is compared to the
  1609  // comment, however the order of the lines is ignored. An example with no such
  1610  // comment is compiled but not executed. An example with no text after
  1611  // "Output:" is compiled, executed, and expected to produce no output.
  1612  //
  1613  // Godoc displays the body of ExampleXXX to demonstrate the use
  1614  // of the function, constant, or variable XXX.  An example of a method M with
  1615  // receiver type T or *T is named ExampleT_M.  There may be multiple examples
  1616  // for a given function, constant, or variable, distinguished by a trailing _xxx,
  1617  // where xxx is a suffix not beginning with an upper case letter.
  1618  //
  1619  // Here is an example of an example:
  1620  //
  1621  // 	func ExamplePrintln() {
  1622  // 		Println("The output of\nthis example.")
  1623  // 		// Output: The output of
  1624  // 		// this example.
  1625  // 	}
  1626  //
  1627  // Here is another example where the ordering of the output is ignored:
  1628  //
  1629  // 	func ExamplePerm() {
  1630  // 		for _, value := range Perm(4) {
  1631  // 			fmt.Println(value)
  1632  // 		}
  1633  //
  1634  // 		// Unordered output: 4
  1635  // 		// 2
  1636  // 		// 1
  1637  // 		// 3
  1638  // 		// 0
  1639  // 	}
  1640  //
  1641  // The entire test file is presented as the example when it contains a single
  1642  // example function, at least one other function, type, variable, or constant
  1643  // declaration, and no test or benchmark functions.
  1644  //
  1645  // See the documentation of the testing package for more information.
  1646  //
  1647  //
  1648  package main