Go Commands - build: Difference between revisions

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==<tt>-o</tt>==
=<tt>-o</tt>=


<tt>-o</tt> flag can only be used when compiling a single package or building an executable. It forces <tt>build</tt> to write the executable or object file to the given file name, instead of the default behavior.
<tt>-o</tt> flag can only be used when compiling a single package or building an executable. It forces <tt>build</tt> to write the executable or object file to the given file name, instead of the default behavior.

Revision as of 17:25, 4 April 2016

Internal

Overview

Depending on the arguments, go build compiles packages or individual files, treating them as part of a single package.

The artifacts are written into the current directory, unless the -o option is used.

Syntax

go build [-o output] [-i] [build flags] [packages]

Building an Executable

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

If that package is "main", build writes the resulting executable to an output file named after the first source file ('go build a.go b.go' writes an "a" executable) or the source code directory ('go build a/b' writes 'b'). The output is overridden by -o flag.


Building a Library

If the arguments are a list of import paths, build compiles the packages named by the import paths, along with their dependencies, but it does not install the results.


-o

-o flag can only be used when compiling a single package or building an executable. It forces build to write the executable or object file to the given file name, instead of the default behavior.



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


The -i flag installs the packages that are dependencies of the target.

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

-a force rebuilding of packages that are already up-to-date. -n print the commands but do not run them. -p n the number of programs, such as build commands or test binaries, that can be run in parallel. The default is the number of CPUs available, except on darwin/arm which defaults to 1. -race enable data race detection. Supported only on linux/amd64, freebsd/amd64, darwin/amd64 and windows/amd64. -msan enable interoperation with memory sanitizer. Supported only on linux/amd64, and only with Clang/LLVM as the host C compiler. -v print the names of packages as they are compiled. -work print the name of the temporary work directory and do not delete it when exiting. -x print the commands.

-asmflags 'flag list' arguments to pass on each go tool asm invocation. -buildmode mode build mode to use. See 'go help buildmode' for more. -compiler name name of compiler to use, as in runtime.Compiler (gccgo or gc). -gccgoflags 'arg list' arguments to pass on each gccgo compiler/linker invocation. -gcflags 'arg list' arguments to pass on each go tool compile invocation. -installsuffix suffix a suffix to use in the name of the package installation directory, in order to keep output separate from default builds. If using the -race flag, the install suffix is automatically set to race or, if set explicitly, has _race appended to it. Likewise for the -msan flag. Using a -buildmode option that requires non-default compile flags has a similar effect. -ldflags 'flag list' arguments to pass on each go tool link invocation. -linkshared link against shared libraries previously created with -buildmode=shared. -pkgdir dir install and load all packages from dir instead of the usual locations. For example, when building with a non-standard configuration, use -pkgdir to keep generated packages in a separate location. -tags 'tag list' a list of build tags to consider satisfied during the build. For more information about build tags, see the description of build constraints in the documentation for the go/build package. -toolexec 'cmd args' a program to use to invoke toolchain programs like vet and asm. For example, instead of running asm, the go command will run 'cmd args /path/to/asm <arguments for asm>'.

The list flags accept a space-separated list of strings. To embed spaces in an element in the list, surround it with either single or double quotes.

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

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

See also: go install, go get, go clean.


go build

builds the current package.

A specific package can be also built:

go build <package-path-string-literal>

where the <package-path-string-literal> is the same literal used by the import statement.

Wildcards can be specified in the package specifiers. A three period indicates a pattern matching any string:

go build something/...

Building an Executable

Building an Executable