for i := 0; i < 1000; i++ {
		wg := &WaitGroup{}
		n := new(int32)
		// spawn goroutine 1
		wg.Add(1)
		go func() {
			atomic.AddInt32(n, 1)
			wg.Done()
		}()
		// spawn goroutine 2
		wg.Add(1)
		go func() {
			atomic.AddInt32(n, 1)
			wg.Done()
		}()
		// Wait for goroutine 1 and 2
		wg.Wait()
		if atomic.LoadInt32(n) != 2 {
			t.Fatal("Spurious wakeup from Wait")
		}
	}
}

// Copyright 2009 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.

//go:build test_run

// Compute Fibonacci numbers with two goroutines
// that pass integers back and forth.  No actual
// concurrency, just threads and synchronization
// and foreign code on multiple pthreads.

package main

import (
	"runtime"
	"strconv"

	"cgostdio/stdio"

		}
	}

	// Set every bit in array to 1.
	a := make([]uint8, 1<<12)
	for i := range a {
		a[i] = 0xff
	}

	// Clear array bit-by-bit in different goroutines.
	done := make(chan bool)
	for i := 0; i < 8; i++ {
		m := ^uint8(1 << i)
		go func() {
			for i := range a {
				atomic.And8(&a[i], m)
			}
			done <- true
		}()
	}

# Check that goroutine scheduling does not affect compiler output.
# If it does, reproducible builds will not work very well.
[short] skip
[GOOS:aix] env CGO_ENABLED=0  # go.dev/issue/56896
env GOMAXPROCS=16
go build -a -o http16.o net/http
env GOMAXPROCS=17
go build -a -o http17.o net/http
cmp -q http16.o http17.o
env GOMAXPROCS=18
go build -a -o http18.o net/http
cmp -q http16.o http18.o

		// In order to generate the nth prime we only need multiples of
		// primes ≤ sqrt(nth prime).  Thus, the merging goroutine will
		// receive from 'primes' much slower than this goroutine
		// will send to it, making the buffer accumulate and block this
		// goroutine from sending, causing a deadlock.  The solution is to
		// use a proxy goroutine to do automatic buffering.
		primes := sendproxy(primes)

		candidates := odds()
		p := <-candidates

package cacher

import (
	"context"
	"sync"
	"testing"
	"time"
)

func Test_newReady(t *testing.T) {
	errCh := make(chan error, 10)
	ready := newReady()
	ready.set(false)
	// create 10 goroutines waiting for ready
	for i := 0; i < 10; i++ {
		go func() {
			errCh <- ready.wait(context.Background())
		}()
	}
	select {
	case <-time.After(1 * time.Second):
	case <-errCh:

)

// wantReads contains the set of values expected to be read by the reader
// goroutine in the tests.
var wantReads []int

func init() {
	for i := 0; i < numWriters; i++ {
		for j := 0; j < numWrites; j++ {
			wantReads = append(wantReads, i)
		}
	}
}

// TestSingleWriter starts one reader and one writer goroutine and makes sure
// that the reader gets all the value added to the buffer by the writer.

			// question response sequence. This allows the
			// test to race thread destruction too.
			once := routines%5 == 4
			go waiter(question, response, once)

			// Keep a count of how many goroutines are
			// going to participate in the
			// question/response test. This will count up
			// towards 2*launches minus the count of
			// routines that have been invoked with
			// once=true.
			routines++

}

func gen(t *testgen.Trace) {
	g := t.Generation(1)

	// One goroutine is exiting with a syscall. It already
	// acquired a new P.
	b0 := g.Batch(trace.ThreadID(0), 0)
	b0.Event("ProcStatus", trace.ProcID(1), go122.ProcRunning)
	b0.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoSyscall)
	b0.Event("GoSyscallEndBlocked")

	// A running goroutine stole P0 at the generation boundary.
	b1 := g.Batch(trace.ThreadID(1), 0)

	wg.Add(2)
	go func() {
		defer wg.Done()
		defer w.Close()
		// Spin before calling Write so that the first ReadFull
		// in the other goroutine will likely be interrupted
		// by a signal.
		sendSomeSignals()
		// This Write will likely be interrupted by a signal
		// as the other goroutine spins in the middle of reading.
		// We write enough data that we should always fill the
		// pipe buffer and need multiple write system calls.