github.com/robhaswell/grandperspective-scan@v0.1.0/test/go-go1.7.1/src/cmd/go/help.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  package main
     6  
     7  var helpC = &Command{
     8  	UsageLine: "c",
     9  	Short:     "calling between Go and C",
    10  	Long: `
    11  There are two different ways to call between Go and C/C++ code.
    12  
    13  The first is the cgo tool, which is part of the Go distribution.  For
    14  information on how to use it see the cgo documentation (go doc cmd/cgo).
    15  
    16  The second is the SWIG program, which is a general tool for
    17  interfacing between languages.  For information on SWIG see
    18  http://swig.org/.  When running go build, any file with a .swig
    19  extension will be passed to SWIG.  Any file with a .swigcxx extension
    20  will be passed to SWIG with the -c++ option.
    21  
    22  When either cgo or SWIG is used, go build will pass any .c, .m, .s,
    23  or .S files to the C compiler, and any .cc, .cpp, .cxx files to the C++
    24  compiler.  The CC or CXX environment variables may be set to determine
    25  the C or C++ compiler, respectively, to use.
    26  	`,
    27  }
    28  
    29  var helpPackages = &Command{
    30  	UsageLine: "packages",
    31  	Short:     "description of package lists",
    32  	Long: `
    33  Many commands apply to a set of packages:
    34  
    35  	go action [packages]
    36  
    37  Usually, [packages] is a list of import paths.
    38  
    39  An import path that is a rooted path or that begins with
    40  a . or .. element is interpreted as a file system path and
    41  denotes the package in that directory.
    42  
    43  Otherwise, the import path P denotes the package found in
    44  the directory DIR/src/P for some DIR listed in the GOPATH
    45  environment variable (see 'go help gopath').
    46  
    47  If no import paths are given, the action applies to the
    48  package in the current directory.
    49  
    50  There are four reserved names for paths that should not be used
    51  for packages to be built with the go tool:
    52  
    53  - "main" denotes the top-level package in a stand-alone executable.
    54  
    55  - "all" expands to all package directories found in all the GOPATH
    56  trees. For example, 'go list all' lists all the packages on the local
    57  system.
    58  
    59  - "std" is like all but expands to just the packages in the standard
    60  Go library.
    61  
    62  - "cmd" expands to the Go repository's commands and their
    63  internal libraries.
    64  
    65  An import path is a pattern if it includes one or more "..." wildcards,
    66  each of which can match any string, including the empty string and
    67  strings containing slashes.  Such a pattern expands to all package
    68  directories found in the GOPATH trees with names matching the
    69  patterns.  As a special case, x/... matches x as well as x's subdirectories.
    70  For example, net/... expands to net and packages in its subdirectories.
    71  
    72  An import path can also name a package to be downloaded from
    73  a remote repository.  Run 'go help importpath' for details.
    74  
    75  Every package in a program must have a unique import path.
    76  By convention, this is arranged by starting each path with a
    77  unique prefix that belongs to you.  For example, paths used
    78  internally at Google all begin with 'google', and paths
    79  denoting remote repositories begin with the path to the code,
    80  such as 'github.com/user/repo'.
    81  
    82  Packages in a program need not have unique package names,
    83  but there are two reserved package names with special meaning.
    84  The name main indicates a command, not a library.
    85  Commands are built into binaries and cannot be imported.
    86  The name documentation indicates documentation for
    87  a non-Go program in the directory. Files in package documentation
    88  are ignored by the go command.
    89  
    90  As a special case, if the package list is a list of .go files from a
    91  single directory, the command is applied to a single synthesized
    92  package made up of exactly those files, ignoring any build constraints
    93  in those files and ignoring any other files in the directory.
    94  
    95  Directory and file names that begin with "." or "_" are ignored
    96  by the go tool, as are directories named "testdata".
    97  	`,
    98  }
    99  
   100  var helpImportPath = &Command{
   101  	UsageLine: "importpath",
   102  	Short:     "import path syntax",
   103  	Long: `
   104  
   105  An import path (see 'go help packages') denotes a package
   106  stored in the local file system.  In general, an import path denotes
   107  either a standard package (such as "unicode/utf8") or a package
   108  found in one of the work spaces (see 'go help gopath').
   109  
   110  Relative import paths
   111  
   112  An import path beginning with ./ or ../ is called a relative path.
   113  The toolchain supports relative import paths as a shortcut in two ways.
   114  
   115  First, a relative path can be used as a shorthand on the command line.
   116  If you are working in the directory containing the code imported as
   117  "unicode" and want to run the tests for "unicode/utf8", you can type
   118  "go test ./utf8" instead of needing to specify the full path.
   119  Similarly, in the reverse situation, "go test .." will test "unicode" from
   120  the "unicode/utf8" directory. Relative patterns are also allowed, like
   121  "go test ./..." to test all subdirectories. See 'go help packages' for details
   122  on the pattern syntax.
   123  
   124  Second, if you are compiling a Go program not in a work space,
   125  you can use a relative path in an import statement in that program
   126  to refer to nearby code also not in a work space.
   127  This makes it easy to experiment with small multipackage programs
   128  outside of the usual work spaces, but such programs cannot be
   129  installed with "go install" (there is no work space in which to install them),
   130  so they are rebuilt from scratch each time they are built.
   131  To avoid ambiguity, Go programs cannot use relative import paths
   132  within a work space.
   133  
   134  Remote import paths
   135  
   136  Certain import paths also
   137  describe how to obtain the source code for the package using
   138  a revision control system.
   139  
   140  A few common code hosting sites have special syntax:
   141  
   142  	Bitbucket (Git, Mercurial)
   143  
   144  		import "bitbucket.org/user/project"
   145  		import "bitbucket.org/user/project/sub/directory"
   146  
   147  	GitHub (Git)
   148  
   149  		import "github.com/user/project"
   150  		import "github.com/user/project/sub/directory"
   151  
   152  	Launchpad (Bazaar)
   153  
   154  		import "launchpad.net/project"
   155  		import "launchpad.net/project/series"
   156  		import "launchpad.net/project/series/sub/directory"
   157  
   158  		import "launchpad.net/~user/project/branch"
   159  		import "launchpad.net/~user/project/branch/sub/directory"
   160  
   161  	IBM DevOps Services (Git)
   162  
   163  		import "hub.jazz.net/git/user/project"
   164  		import "hub.jazz.net/git/user/project/sub/directory"
   165  
   166  For code hosted on other servers, import paths may either be qualified
   167  with the version control type, or the go tool can dynamically fetch
   168  the import path over https/http and discover where the code resides
   169  from a <meta> tag in the HTML.
   170  
   171  To declare the code location, an import path of the form
   172  
   173  	repository.vcs/path
   174  
   175  specifies the given repository, with or without the .vcs suffix,
   176  using the named version control system, and then the path inside
   177  that repository.  The supported version control systems are:
   178  
   179  	Bazaar      .bzr
   180  	Git         .git
   181  	Mercurial   .hg
   182  	Subversion  .svn
   183  
   184  For example,
   185  
   186  	import "example.org/user/foo.hg"
   187  
   188  denotes the root directory of the Mercurial repository at
   189  example.org/user/foo or foo.hg, and
   190  
   191  	import "example.org/repo.git/foo/bar"
   192  
   193  denotes the foo/bar directory of the Git repository at
   194  example.org/repo or repo.git.
   195  
   196  When a version control system supports multiple protocols,
   197  each is tried in turn when downloading.  For example, a Git
   198  download tries https://, then git+ssh://.
   199  
   200  If the import path is not a known code hosting site and also lacks a
   201  version control qualifier, the go tool attempts to fetch the import
   202  over https/http and looks for a <meta> tag in the document's HTML
   203  <head>.
   204  
   205  The meta tag has the form:
   206  
   207  	<meta name="go-import" content="import-prefix vcs repo-root">
   208  
   209  The import-prefix is the import path corresponding to the repository
   210  root. It must be a prefix or an exact match of the package being
   211  fetched with "go get". If it's not an exact match, another http
   212  request is made at the prefix to verify the <meta> tags match.
   213  
   214  The meta tag should appear as early in the file as possible.
   215  In particular, it should appear before any raw JavaScript or CSS,
   216  to avoid confusing the go command's restricted parser.
   217  
   218  The vcs is one of "git", "hg", "svn", etc,
   219  
   220  The repo-root is the root of the version control system
   221  containing a scheme and not containing a .vcs qualifier.
   222  
   223  For example,
   224  
   225  	import "example.org/pkg/foo"
   226  
   227  will result in the following requests:
   228  
   229  	https://example.org/pkg/foo?go-get=1 (preferred)
   230  	http://example.org/pkg/foo?go-get=1  (fallback, only with -insecure)
   231  
   232  If that page contains the meta tag
   233  
   234  	<meta name="go-import" content="example.org git https://code.org/r/p/exproj">
   235  
   236  the go tool will verify that https://example.org/?go-get=1 contains the
   237  same meta tag and then git clone https://code.org/r/p/exproj into
   238  GOPATH/src/example.org.
   239  
   240  New downloaded packages are written to the first directory
   241  listed in the GOPATH environment variable (see 'go help gopath').
   242  
   243  The go command attempts to download the version of the
   244  package appropriate for the Go release being used.
   245  Run 'go help get' for more.
   246  
   247  Import path checking
   248  
   249  When the custom import path feature described above redirects to a
   250  known code hosting site, each of the resulting packages has two possible
   251  import paths, using the custom domain or the known hosting site.
   252  
   253  A package statement is said to have an "import comment" if it is immediately
   254  followed (before the next newline) by a comment of one of these two forms:
   255  
   256  	package math // import "path"
   257  	package math /* import "path" */
   258  
   259  The go command will refuse to install a package with an import comment
   260  unless it is being referred to by that import path. In this way, import comments
   261  let package authors make sure the custom import path is used and not a
   262  direct path to the underlying code hosting site.
   263  
   264  Import path checking is disabled for code found within vendor trees.
   265  This makes it possible to copy code into alternate locations in vendor trees
   266  without needing to update import comments.
   267  
   268  See https://golang.org/s/go14customimport for details.
   269  	`,
   270  }
   271  
   272  var helpGopath = &Command{
   273  	UsageLine: "gopath",
   274  	Short:     "GOPATH environment variable",
   275  	Long: `
   276  The Go path is used to resolve import statements.
   277  It is implemented by and documented in the go/build package.
   278  
   279  The GOPATH environment variable lists places to look for Go code.
   280  On Unix, the value is a colon-separated string.
   281  On Windows, the value is a semicolon-separated string.
   282  On Plan 9, the value is a list.
   283  
   284  GOPATH must be set to get, build and install packages outside the
   285  standard Go tree.
   286  
   287  Each directory listed in GOPATH must have a prescribed structure:
   288  
   289  The src directory holds source code.  The path below src
   290  determines the import path or executable name.
   291  
   292  The pkg directory holds installed package objects.
   293  As in the Go tree, each target operating system and
   294  architecture pair has its own subdirectory of pkg
   295  (pkg/GOOS_GOARCH).
   296  
   297  If DIR is a directory listed in the GOPATH, a package with
   298  source in DIR/src/foo/bar can be imported as "foo/bar" and
   299  has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a".
   300  
   301  The bin directory holds compiled commands.
   302  Each command is named for its source directory, but only
   303  the final element, not the entire path.  That is, the
   304  command with source in DIR/src/foo/quux is installed into
   305  DIR/bin/quux, not DIR/bin/foo/quux.  The "foo/" prefix is stripped
   306  so that you can add DIR/bin to your PATH to get at the
   307  installed commands.  If the GOBIN environment variable is
   308  set, commands are installed to the directory it names instead
   309  of DIR/bin. GOBIN must be an absolute path.
   310  
   311  Here's an example directory layout:
   312  
   313      GOPATH=/home/user/gocode
   314  
   315      /home/user/gocode/
   316          src/
   317              foo/
   318                  bar/               (go code in package bar)
   319                      x.go
   320                  quux/              (go code in package main)
   321                      y.go
   322          bin/
   323              quux                   (installed command)
   324          pkg/
   325              linux_amd64/
   326                  foo/
   327                      bar.a          (installed package object)
   328  
   329  Go searches each directory listed in GOPATH to find source code,
   330  but new packages are always downloaded into the first directory
   331  in the list.
   332  
   333  See https://golang.org/doc/code.html for an example.
   334  
   335  Internal Directories
   336  
   337  Code in or below a directory named "internal" is importable only
   338  by code in the directory tree rooted at the parent of "internal".
   339  Here's an extended version of the directory layout above:
   340  
   341      /home/user/gocode/
   342          src/
   343              crash/
   344                  bang/              (go code in package bang)
   345                      b.go
   346              foo/                   (go code in package foo)
   347                  f.go
   348                  bar/               (go code in package bar)
   349                      x.go
   350                  internal/
   351                      baz/           (go code in package baz)
   352                          z.go
   353                  quux/              (go code in package main)
   354                      y.go
   355  
   356  
   357  The code in z.go is imported as "foo/internal/baz", but that
   358  import statement can only appear in source files in the subtree
   359  rooted at foo. The source files foo/f.go, foo/bar/x.go, and
   360  foo/quux/y.go can all import "foo/internal/baz", but the source file
   361  crash/bang/b.go cannot.
   362  
   363  See https://golang.org/s/go14internal for details.
   364  
   365  Vendor Directories
   366  
   367  Go 1.6 includes support for using local copies of external dependencies
   368  to satisfy imports of those dependencies, often referred to as vendoring.
   369  
   370  Code below a directory named "vendor" is importable only
   371  by code in the directory tree rooted at the parent of "vendor",
   372  and only using an import path that omits the prefix up to and
   373  including the vendor element.
   374  
   375  Here's the example from the previous section,
   376  but with the "internal" directory renamed to "vendor"
   377  and a new foo/vendor/crash/bang directory added:
   378  
   379      /home/user/gocode/
   380          src/
   381              crash/
   382                  bang/              (go code in package bang)
   383                      b.go
   384              foo/                   (go code in package foo)
   385                  f.go
   386                  bar/               (go code in package bar)
   387                      x.go
   388                  vendor/
   389                      crash/
   390                          bang/      (go code in package bang)
   391                              b.go
   392                      baz/           (go code in package baz)
   393                          z.go
   394                  quux/              (go code in package main)
   395                      y.go
   396  
   397  The same visibility rules apply as for internal, but the code
   398  in z.go is imported as "baz", not as "foo/vendor/baz".
   399  
   400  Code in vendor directories deeper in the source tree shadows
   401  code in higher directories. Within the subtree rooted at foo, an import
   402  of "crash/bang" resolves to "foo/vendor/crash/bang", not the
   403  top-level "crash/bang".
   404  
   405  Code in vendor directories is not subject to import path
   406  checking (see 'go help importpath').
   407  
   408  When 'go get' checks out or updates a git repository, it now also
   409  updates submodules.
   410  
   411  Vendor directories do not affect the placement of new repositories
   412  being checked out for the first time by 'go get': those are always
   413  placed in the main GOPATH, never in a vendor subtree.
   414  
   415  See https://golang.org/s/go15vendor for details.
   416  	`,
   417  }
   418  
   419  var helpEnvironment = &Command{
   420  	UsageLine: "environment",
   421  	Short:     "environment variables",
   422  	Long: `
   423  
   424  The go command, and the tools it invokes, examine a few different
   425  environment variables. For many of these, you can see the default
   426  value of on your system by running 'go env NAME', where NAME is the
   427  name of the variable.
   428  
   429  General-purpose environment variables:
   430  
   431  	GCCGO
   432  		The gccgo command to run for 'go build -compiler=gccgo'.
   433  	GOARCH
   434  		The architecture, or processor, for which to compile code.
   435  		Examples are amd64, 386, arm, ppc64.
   436  	GOBIN
   437  		The directory where 'go install' will install a command.
   438  	GOOS
   439  		The operating system for which to compile code.
   440  		Examples are linux, darwin, windows, netbsd.
   441  	GOPATH
   442  		See 'go help gopath'.
   443  	GORACE
   444  		Options for the race detector.
   445  		See https://golang.org/doc/articles/race_detector.html.
   446  	GOROOT
   447  		The root of the go tree.
   448  
   449  Environment variables for use with cgo:
   450  
   451  	CC
   452  		The command to use to compile C code.
   453  	CGO_ENABLED
   454  		Whether the cgo command is supported.  Either 0 or 1.
   455  	CGO_CFLAGS
   456  		Flags that cgo will pass to the compiler when compiling
   457  		C code.
   458  	CGO_CPPFLAGS
   459  		Flags that cgo will pass to the compiler when compiling
   460  		C or C++ code.
   461  	CGO_CXXFLAGS
   462  		Flags that cgo will pass to the compiler when compiling
   463  		C++ code.
   464  	CGO_LDFLAGS
   465  		Flags that cgo will pass to the compiler when linking.
   466  	CXX
   467  		The command to use to compile C++ code.
   468  
   469  Architecture-specific environment variables:
   470  
   471  	GOARM
   472  		For GOARCH=arm, the ARM architecture for which to compile.
   473  		Valid values are 5, 6, 7.
   474  	GO386
   475  		For GOARCH=386, the floating point instruction set.
   476  		Valid values are 387, sse2.
   477  
   478  Special-purpose environment variables:
   479  
   480  	GOROOT_FINAL
   481  		The root of the installed Go tree, when it is
   482  		installed in a location other than where it is built.
   483  		File names in stack traces are rewritten from GOROOT to
   484  		GOROOT_FINAL.
   485  	GO_EXTLINK_ENABLED
   486  		Whether the linker should use external linking mode
   487  		when using -linkmode=auto with code that uses cgo.
   488  		Set to 0 to disable external linking mode, 1 to enable it.
   489  	`,
   490  }
   491  
   492  var helpFileType = &Command{
   493  	UsageLine: "filetype",
   494  	Short:     "file types",
   495  	Long: `
   496  The go command examines the contents of a restricted set of files
   497  in each directory. It identifies which files to examine based on
   498  the extension of the file name. These extensions are:
   499  
   500  	.go
   501  		Go source files.
   502  	.c, .h
   503  		C source files.
   504  		If the package uses cgo or SWIG, these will be compiled with the
   505  		OS-native compiler (typically gcc); otherwise they will
   506  		trigger an error.
   507  	.cc, .cpp, .cxx, .hh, .hpp, .hxx
   508  		C++ source files. Only useful with cgo or SWIG, and always
   509  		compiled with the OS-native compiler.
   510  	.m
   511  		Objective-C source files. Only useful with cgo, and always
   512  		compiled with the OS-native compiler.
   513  	.s, .S
   514  		Assembler source files.
   515  		If the package uses cgo or SWIG, these will be assembled with the
   516  		OS-native assembler (typically gcc (sic)); otherwise they
   517  		will be assembled with the Go assembler.
   518  	.swig, .swigcxx
   519  		SWIG definition files.
   520  	.syso
   521  		System object files.
   522  
   523  Files of each of these types except .syso may contain build
   524  constraints, but the go command stops scanning for build constraints
   525  at the first item in the file that is not a blank line or //-style
   526  line comment. See the go/build package documentation for
   527  more details.
   528  
   529  Non-test Go source files can also include a //go:binary-only-package
   530  comment, indicating that the package sources are included
   531  for documentation only and must not be used to build the
   532  package binary. This enables distribution of Go packages in
   533  their compiled form alone. See the go/build package documentation
   534  for more details.
   535  	`,
   536  }
   537  
   538  var helpBuildmode = &Command{
   539  	UsageLine: "buildmode",
   540  	Short:     "description of build modes",
   541  	Long: `
   542  The 'go build' and 'go install' commands take a -buildmode argument which
   543  indicates which kind of object file is to be built. Currently supported values
   544  are:
   545  
   546  	-buildmode=archive
   547  		Build the listed non-main packages into .a files. Packages named
   548  		main are ignored.
   549  
   550  	-buildmode=c-archive
   551  		Build the listed main package, plus all packages it imports,
   552  		into a C archive file. The only callable symbols will be those
   553  		functions exported using a cgo //export comment. Requires
   554  		exactly one main package to be listed.
   555  
   556  	-buildmode=c-shared
   557  		Build the listed main packages, plus all packages that they
   558  		import, into C shared libraries. The only callable symbols will
   559  		be those functions exported using a cgo //export comment.
   560  		Non-main packages are ignored.
   561  
   562  	-buildmode=default
   563  		Listed main packages are built into executables and listed
   564  		non-main packages are built into .a files (the default
   565  		behavior).
   566  
   567  	-buildmode=shared
   568  		Combine all the listed non-main packages into a single shared
   569  		library that will be used when building with the -linkshared
   570  		option. Packages named main are ignored.
   571  
   572  	-buildmode=exe
   573  		Build the listed main packages and everything they import into
   574  		executables. Packages not named main are ignored.
   575  
   576  	-buildmode=pie
   577  		Build the listed main packages and everything they import into
   578  		position independent executables (PIE). Packages not named
   579  		main are ignored.
   580  `,
   581  }