// syncTimer returns c as an unsafe.Pointer, for passing to newTimer.
// If the GODEBUG asynctimerchan has disabled the async timer chan
// code, then syncTimer always returns nil, to disable the special
// channel code paths in the runtime.
func syncTimer(c chan Time) unsafe.Pointer {
	// If asynctimerchan=1, we don't even tell the runtime
	// about channel timers, so that we get the pre-Go 1.23 code paths.

	// zero will knock off any existing values of keep-alive.
	// Unfortunately, Windows doesn't support retrieving current keep-alive
	// settings in any form programmatically, which disable us to first retrieve
	// the current keep-alive settings, then set it without unwanted corruption.
	switch {
	case idle < 0 && interval >= 0:
		// Given that we can't set KeepAliveInterval alone, and this code path

func (p *Pool) Put(x any) {
	if x == nil {
		return
	}
	if race.Enabled {
		if runtime_randn(4) == 0 {
			// Randomly drop x on floor.
			return
		}
		race.ReleaseMerge(poolRaceAddr(x))
		race.Disable()
	}
	l, _ := p.pin()
	if l.private == nil {
		l.private = x
	} else {
		l.shared.pushHead(x)
	}
	runtime_procUnpin()
	if race.Enabled {
		race.Enable()
	}
}

// refers to a field of T, whereas for the other types it refers to a
// value in the environment.
//
// New programs should set the [parser.SkipObjectResolution] parser
// flag to disable syntactic object resolution (which also saves CPU
// and memory), and instead use the type checker [go/types] if object
// resolution is desired. See the Defs, Uses, and Implicits fields of
// the [types.Info] struct for details.

				fatal("%v", err)
			}
			if err = f.Close(); err != nil {
				fatal("error closing memory profile: %v", err)
			}
		})
	} else {
		// Not doing memory profiling; disable it entirely.
		runtime.MemProfileRate = 0
	}

	// Mode-dependent setup.
	op.Setup()

	// ... off and running now.
	dbgtrace(1, "starting perform")

	indirs := strings.Split(*indirsflag, ",")

	-buildmode mode
		Set build mode (default exe).
	-c
		Dump call graphs.
	-compressdwarf
		Compress DWARF if possible (default true).
	-cpuprofile file
		Write CPU profile to file.
	-d
		Disable generation of dynamic executables.
		The emitted code is the same in either case; the option
		controls only whether a dynamic header is included.
		The dynamic header is on by default, even without any

// See the WaitGroup example.
func (wg *WaitGroup) Add(delta int) {
	if race.Enabled {
		if delta < 0 {
			// Synchronize decrements with Wait.
			race.ReleaseMerge(unsafe.Pointer(wg))
		}
		race.Disable()
		defer race.Enable()
	}
	state := wg.state.Add(uint64(delta) << 32)
	v := int32(state >> 32)
	w := uint32(state)
	if race.Enabled && delta > 0 && v == int32(delta) {

	}

	if debug.harddecommit > 0 {
		p, err := mmap(v, n, _PROT_NONE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)
		if p != v || err != 0 {
			throw("runtime: cannot disable permissions in address space")
		}
	}
}

func sysUsedOS(v unsafe.Pointer, n uintptr) {
	if debug.harddecommit > 0 {
		p, err := mmap(v, n, _PROT_READ|_PROT_WRITE, _MAP_ANON|_MAP_FIXED|_MAP_PRIVATE, -1, 0)

// panic.
//
// The fallback behavior can be forced on all platforms, even when there is a
// system certificate pool, by setting GODEBUG=x509usefallbackroots=1 (note that
// on Windows and macOS this will disable usage of the platform verification
// APIs and cause the pure Go verifier to be used). Setting
// x509usefallbackroots=1 without calling SetFallbackRoots has no effect.
func SetFallbackRoots(roots *CertPool) {
	if roots == nil {

//
//go:build !race

package sync_test

import (
	"runtime"
	"runtime/debug"
	"slices"
	. "sync"
	"sync/atomic"
	"testing"
	"time"
)

func TestPool(t *testing.T) {
	// disable GC so we can control when it happens.
	defer debug.SetGCPercent(debug.SetGCPercent(-1))
	var p Pool
	if p.Get() != nil {
		t.Fatal("expected empty")
	}

	// Make sure that the goroutine doesn't migrate to another P