return
}

// SupportSockNonblockCloexec tests if SOCK_NONBLOCK and SOCK_CLOEXEC are supported
// for socket() system call, returns true if affirmative.
var SupportSockNonblockCloexec = sync.OnceValue(func() bool {
	// First test if socket() supports SOCK_NONBLOCK and SOCK_CLOEXEC directly.
	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, 0)
	if err == nil {
		syscall.Close(s)

	"runtime"
	"syscall"
	"testing"
)

func TestSupportSockNonblockCloexec(t *testing.T) {
	// Test that SupportSockNonblockCloexec returns true if socket succeeds with SOCK_NONBLOCK and SOCK_CLOEXEC.
	s, err := syscall.Socket(syscall.AF_INET, syscall.SOCK_STREAM|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, 0)
	if err == nil {
		syscall.Close(s)
	}
	wantSock := err != syscall.EPROTONOSUPPORT && err != syscall.EINVAL

)

// Wrapper around the socket system call that marks the returned file
// descriptor as nonblocking and close-on-exec.
func sysSocket(family, sotype, proto int) (int, error) {
	s, err := socketFunc(family, sotype|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, proto)
	if err != nil {
		return -1, os.NewSyscallError("socket", err)
	}
	return s, nil

// Wrapper around the accept system call that marks the returned file
// descriptor as nonblocking and close-on-exec.
func accept(s int) (int, syscall.Sockaddr, string, error) {
	ns, sa, err := Accept4Func(s, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC)
	if err != nil {
		return -1, nil, "accept4", err
	}
	return ns, sa, "", nil

func accept(s int) (int, syscall.Sockaddr, string, error) {
	// Perform a cheap test and try the fast path first.
	if unix.SupportAccept4() {
		ns, sa, err := Accept4Func(s, syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC)
		if err != nil {
			return -1, nil, "accept4", err
		}
		return ns, sa, "", nil
	}

	// See ../syscall/exec_unix.go for description of ForkLock.

func sysSocket(family, sotype, proto int) (int, error) {
	// Perform a cheap test and try the fast path first.
	if unix.SupportSockNonblockCloexec() {
		s, err := socketFunc(family, sotype|syscall.SOCK_NONBLOCK|syscall.SOCK_CLOEXEC, proto)
		if err != nil {
			return -1, os.NewSyscallError("socket", err)
		}
		return s, nil
	}

	// See ../syscall/exec_unix.go for description of ForkLock.
	syscall.ForkLock.RLock()

	SIOCINQ                          = 0x467f
	SIOCOUTQ                         = 0x7472
	SIOCSPGRP                        = 0x80047308
	SOCK_CLOEXEC                     = 0x80000
	SOCK_DGRAM                       = 0x1
	SOCK_NONBLOCK                    = 0x80
	SOCK_STREAM                      = 0x2
	SOL_SOCKET                       = 0xffff
	SO_ACCEPTCONN                    = 0x1009
	SO_ATTACH_BPF                    = 0x32

	SIOCINQ                          = 0x541b
	SIOCOUTQ                         = 0x5411
	SIOCSPGRP                        = 0x8902
	SOCK_CLOEXEC                     = 0x80000
	SOCK_DGRAM                       = 0x2
	SOCK_NONBLOCK                    = 0x800
	SOCK_STREAM                      = 0x1
	SOL_SOCKET                       = 0x1
	SO_ACCEPTCONN                    = 0x1e
	SO_ATTACH_BPF                    = 0x32

	SIOCINQ                          = 0x541b
	SIOCOUTQ                         = 0x5411
	SIOCSPGRP                        = 0x8902
	SOCK_CLOEXEC                     = 0x80000
	SOCK_DGRAM                       = 0x2
	SOCK_NONBLOCK                    = 0x800
	SOCK_STREAM                      = 0x1
	SOL_SOCKET                       = 0x1
	SO_ACCEPTCONN                    = 0x1e
	SO_ATTACH_BPF                    = 0x32

	SIOCINQ                          = 0x541b
	SIOCOUTQ                         = 0x5411
	SIOCSPGRP                        = 0x8902
	SOCK_CLOEXEC                     = 0x80000
	SOCK_DGRAM                       = 0x2
	SOCK_NONBLOCK                    = 0x800
	SOCK_STREAM                      = 0x1
	SOL_SOCKET                       = 0x1
	SO_ACCEPTCONN                    = 0x1e
	SO_ATTACH_BPF                    = 0x32