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// Copyright 2023 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 main
import (
"os"
"sync"
"syscall"
)
func main() {
if len(os.Args) < 2 {
panic("usage: nonblock <MODE> [PATH...]")
}
mode := os.Args[1]
ready := make(chan struct{})
var wg sync.WaitGroup
for _, path := range os.Args[2:] {
f, err := os.Open(path)
if err != nil {
panic(err)
}
switch mode {
case "os.OpenFile":
case "os.NewFile":
fd := f.Fd()
if err := syscall.SetNonblock(int(fd), true); err != nil {
panic(err)
}
f = os.NewFile(fd, path)
default:
panic("invalid test mode")
}
spawnWait := make(chan struct{})
wg.Add(1)
go func(f *os.File) {
defer f.Close()
defer wg.Done()
close(spawnWait)
<-ready
var buf [256]byte
n, err := f.Read(buf[:])
if err != nil {
panic(err)
}
os.Stderr.Write(buf[:n])
}(f)
// Spawn one goroutine at a time.
<-spawnWait
}
println("waiting")
close(ready)
wg.Wait()
}
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