//sys	fcntl(fd int, cmd int, arg int) (n int, err error)
//sys	fcntlPtr(fd int, cmd int, arg unsafe.Pointer) (n int, err error) = SYS_FCNTL

// FcntlInt performs a fcntl syscall on fd with the provided command and argument.
func FcntlInt(fd uintptr, cmd, arg int) (int, error) {
	return fcntl(int(fd), cmd, arg)
}

// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command.

// This code implements the filelock API using POSIX 'fcntl' locks, which attach
// to an (inode, process) pair rather than a file descriptor. To avoid unlocking
// files prematurely when the same file is opened through different descriptors,
// we allow only one read-lock at a time.
//
// Most platforms provide some alternative API, such as an 'flock' system call
// or an F_OFD_SETLK command for 'fcntl', that allows for better concurrency and

*/

package runtime

/*
#include <sys/types.h>
#include <sys/event.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <sys/unistd.h>
#include <sys/signal.h>
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
*/
import "C"

const (
	EINTR     = C.EINTR
	EFAULT    = C.EFAULT
	EAGAIN    = C.EAGAIN
	ETIMEDOUT = C.ETIMEDOUT

	O_NONBLOCK = C.O_NONBLOCK

}

func CloseOnExec(fd int) { fcntl(fd, F_SETFD, FD_CLOEXEC) }

func SetNonblock(fd int, nonblocking bool) (err error) {
	flag, err := fcntl(fd, F_GETFL, 0)
	if err != nil {
		return err
	}
	if (flag&O_NONBLOCK != 0) == nonblocking {
		return nil
	}
	if nonblocking {
		flag |= O_NONBLOCK
	} else {
		flag &^= O_NONBLOCK
	}
	_, err = fcntl(fd, F_SETFL, flag)
	return err
}

		t.Fatalf("got FDs %#v: wanted only 1 fd", gotFDs)
	}
	defer func() {
		if err := syscall.Close(gotFDs[0]); err != nil {
			t.Fatalf("fail to close gotFDs: %v", err)
		}
	}()

	flags, err := unix.Fcntl(gotFDs[0], syscall.F_GETFD, 0)
	if err != nil {
		t.Fatalf("Can't get flags of fd:%#v, with err:%v", gotFDs[0], err)
	}
	if flags&syscall.FD_CLOEXEC == 0 {

#include <sys/ptrace.h>
#include <sys/statfs.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <netinet/in.h>
#include <netinet/icmp6.h>

#include <termios.h>

#include <dirent.h>
#include <fcntl.h>
#include <gcrypt.h>

enum {
	sizeofPtr = sizeof(void*),
};

union sockaddr_all {
	struct sockaddr s1;	// this one gets used for fields
	struct sockaddr_in s2;	// these pad it out
	struct sockaddr_in6 s3;

// +godefs map struct_in6_addr [16]byte /* in6_addr */

package syscall

/*
#define __DARWIN_UNIX03 0
#define KERNEL
#define _DARWIN_USE_64_BIT_INODE
#include <dirent.h>
#include <fcntl.h>
#include <signal.h>
#include <termios.h>
#include <unistd.h>
#include <mach/mach.h>
#include <mach/message.h>
#include <sys/event.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/param.h>

// munmap calls the munmap system call. It is implemented in assembly.
func munmap(addr unsafe.Pointer, n uintptr)

func nanotime1() int64

//go:noescape
func sigaltstack(new, old *stackt)

func fcntl(fd, cmd, arg int32) (ret int32, errno int32)

func walltime() (sec int64, nsec int32)

// Not used on Darwin, but must be defined.
func exitThread(wait *atomic.Uint32) {
	throw("exitThread")
}

//go:nosplit
func setNonblock(fd int32) {
	flags, _ := fcntl(fd, _F_GETFL, 0)
	if flags != -1 {
		fcntl(fd, _F_SETFL, flags|_O_NONBLOCK)
	}
}

func issetugid() int32 {
	return libcCall(unsafe.Pointer(abi.FuncPCABI0(issetugid_trampoline)), nil)
}
func issetugid_trampoline()

#define pid_t int
#include <asm/signal.h>
#include <asm/mman.h>
#include <asm/sigcontext.h>
#include <asm/ucontext.h>
#include <asm/siginfo.h>
#include <asm-generic/errno.h>
#include <asm-generic/fcntl.h>
#include <asm-generic/poll.h>
#include <linux/eventpoll.h>

// This is the sigaction structure from the Linux 2.1.68 kernel which
//   is used with the rt_sigaction system call. For 386 this is not