diff options
| author | Ian Lance Taylor <iant@golang.org> | 2020-12-23 09:57:37 -0800 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2020-12-30 15:13:24 -0800 |
| commit | cfcbb4227fb20191e04eb8d7766ae6202f526afd (patch) | |
| tree | e2effea96f6f204451779f044415c2385e45042b /libgo/go/flag/example_func_test.go | |
| parent | 0696141107d61483f38482b941549959a0d7f613 (diff) | |
| download | gcc-cfcbb4227fb20191e04eb8d7766ae6202f526afd.zip gcc-cfcbb4227fb20191e04eb8d7766ae6202f526afd.tar.gz gcc-cfcbb4227fb20191e04eb8d7766ae6202f526afd.tar.bz2 | |
libgo: update to Go1.16beta1 release
This does not yet include support for the //go:embed directive added
in this release.
* Makefile.am (check-runtime): Don't create check-runtime-dir.
(mostlyclean-local): Don't remove check-runtime-dir.
(check-go-tool, check-vet): Copy in go.mod and modules.txt.
(check-cgo-test, check-carchive-test): Add go.mod file.
* Makefile.in: Regenerate.
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/280172
Diffstat (limited to 'libgo/go/flag/example_func_test.go')
| -rw-r--r-- | libgo/go/flag/example_func_test.go | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/libgo/go/flag/example_func_test.go b/libgo/go/flag/example_func_test.go new file mode 100644 index 0000000..7c30c5e --- /dev/null +++ b/libgo/go/flag/example_func_test.go @@ -0,0 +1,41 @@ +// Copyright 2020 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package flag_test + +import ( + "errors" + "flag" + "fmt" + "net" + "os" +) + +func ExampleFunc() { + fs := flag.NewFlagSet("ExampleFunc", flag.ContinueOnError) + fs.SetOutput(os.Stdout) + var ip net.IP + fs.Func("ip", "`IP address` to parse", func(s string) error { + ip = net.ParseIP(s) + if ip == nil { + return errors.New("could not parse IP") + } + return nil + }) + fs.Parse([]string{"-ip", "127.0.0.1"}) + fmt.Printf("{ip: %v, loopback: %t}\n\n", ip, ip.IsLoopback()) + + // 256 is not a valid IPv4 component + fs.Parse([]string{"-ip", "256.0.0.1"}) + fmt.Printf("{ip: %v, loopback: %t}\n\n", ip, ip.IsLoopback()) + + // Output: + // {ip: 127.0.0.1, loopback: true} + // + // invalid value "256.0.0.1" for flag -ip: could not parse IP + // Usage of ExampleFunc: + // -ip IP address + // IP address to parse + // {ip: <nil>, loopback: false} +} |