// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package sync

// OnceFunc returns a function that invokes f only once. The returned function
// may be called concurrently.
//
// If f panics, the returned function will panic with the same value on every call.
func OnceFunc(f func()) func() {
	var (
		once  Once
		valid bool
		p     any
	)

			// never mutated and is a closure that could be inlined.
			// Too bad, because this is how OnceFunc will usually be used.
			onceFunc()
		}
	})
	b.Run("v=Local", func(b *testing.B) {
		b.ReportAllocs()
		// As of 3/2023, the compiler *does* recognize this local binding as an
		// inlinable closure. This is the best case for OnceFunc, but probably
		// not typical usage.

			"(*rngSource).Int63",
			"(*rngSource).Uint64",
		},
		"net": {
			"(*UDPConn).ReadFromUDP",
		},
		"sync": {
			// Both OnceFunc and its returned closure need to be inlinable so
			// that the returned closure can be inlined into the caller of OnceFunc.
			"OnceFunc",
			"OnceFunc.func2", // The returned closure.
			// TODO(austin): It would be good to check OnceValue and OnceValues,

	return info.majorVersion, info.minorVersion, info.buildNumber
}

var (
	supportTCPKeepAliveIdle     bool
	supportTCPKeepAliveInterval bool
	supportTCPKeepAliveCount    bool
)

var initTCPKeepAlive = sync.OnceFunc(func() {
	s, err := WSASocket(syscall.AF_INET, syscall.SOCK_STREAM, syscall.IPPROTO_TCP, nil, 0, WSA_FLAG_NO_HANDLE_INHERIT)
	if err != nil {
		// Fallback to checking the Windows version.
		major, _, build := version()

pkg slices, func SortStableFunc[$0 interface{ ~[]$1 }, $1 interface{}]($0, func($1, $1) int) #60091
pkg strings, func ContainsFunc(string, func(int32) bool) bool #54386
pkg sync, func OnceFunc(func()) func() #56102
pkg sync, func OnceValue[$0 interface{}](func() $0) func() $0 #56102
pkg sync, func OnceValues[$0 interface{}, $1 interface{}](func() ($0, $1)) func() ($0, $1) #56102

}

// InitWSA initiates the use of the Winsock DLL by the current process.
// It is called from the net package at init time to avoid
// loading ws2_32.dll when net is not used.
var InitWSA = sync.OnceFunc(func() {
	var d syscall.WSAData
	e := syscall.WSAStartup(uint32(0x202), &d)
	if e != nil {
		initErr = e
	}
	checkSetFileCompletionNotificationModes()
})

		{"(*WaitGroup).Wait", Method, 0},
		{"Cond", Type, 0},
		{"Cond.L", Field, 0},
		{"Locker", Type, 0},
		{"Map", Type, 9},
		{"Mutex", Type, 0},
		{"NewCond", Func, 0},
		{"Once", Type, 0},
		{"OnceFunc", Func, 21},
		{"OnceValue", Func, 21},
		{"OnceValues", Func, 21},
		{"Pool", Type, 3},
		{"Pool.New", Field, 3},
		{"RWMutex", Type, 0},
		{"WaitGroup", Type, 0},
	},
	"sync/atomic": {