text: /* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to
   * deal in the Software without restriction, including without limitation the
   * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
   * sell copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   * IN THE SOFTWARE.
   */
  
  /* See http://nikhilm.github.com/uvbook/ for an introduction. */
  
  #ifndef UV_H
  #define UV_H
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #ifdef _WIN32
    /* Windows - set up dll import/export decorators. */
  # if defined(BUILDING_UV_SHARED)
      /* Building shared library. */
  #   define UV_EXTERN __declspec(dllexport)
  # elif defined(USING_UV_SHARED)
      /* Using shared library. */
  #   define UV_EXTERN __declspec(dllimport)
  # else
      /* Building static library. */
  #   define UV_EXTERN /* nothing */
  # endif
  #elif __GNUC__ >= 4
  # define UV_EXTERN __attribute__((visibility("default")))
  #else
  # define UV_EXTERN /* nothing */
  #endif
  
  #include "uv-errno.h"
  
  #if defined(_MSC_VER) && _MSC_VER < 1600
  # include "stdint-msvc2008.h"
  #else
  # include <stdint.h>
  #endif
  
  #include <sys/types.h> /* size_t */
  
  #if defined(__SVR4) && !defined(__unix__)
  # define __unix__
  #endif
  
  #if defined(__unix__) || defined(__POSIX__) || \
      defined(__APPLE__) || defined(_AIX)
  # include "uv-unix.h"
  #else
  # include "uv-win.h"
  #endif
  
  /* Expand this list if necessary. */
  #define UV_ERRNO_MAP(XX)                                                      \
    XX(EACCES, "permission denied")                                             \
    XX(EADDRINUSE, "address already in use")                                    \
    XX(EADDRNOTAVAIL, "address not available")                                  \
    XX(EAFNOSUPPORT, "address family not supported")                            \
    XX(EAGAIN, "resource temporarily unavailable")                              \
    XX(EAI_ADDRFAMILY, "address family not supported")                          \
    XX(EAI_AGAIN, "temporary failure")                                          \
    XX(EAI_BADFLAGS, "bad ai_flags value")                                      \
    XX(EAI_CANCELED, "request canceled")                                        \
    XX(EAI_FAIL, "permanent failure")                                           \
    XX(EAI_FAMILY, "ai_family not supported")                                   \
    XX(EAI_MEMORY, "out of memory")                                             \
    XX(EAI_NODATA, "no address")                                                \
    XX(EAI_NONAME, "unknown node or service")                                   \
    XX(EAI_SERVICE, "service not available for socket type")                    \
    XX(EAI_SOCKTYPE, "socket type not supported")                               \
    XX(EAI_SYSTEM, "system error")                                              \
    XX(EALREADY, "connection already in progress")                              \
    XX(EBADF, "bad file descriptor")                                            \
    XX(EBUSY, "resource busy or locked")                                        \
    XX(ECANCELED, "operation canceled")                                         \
    XX(ECHARSET, "invalid Unicode character")                                   \
    XX(ECONNABORTED, "software caused connection abort")                        \
    XX(ECONNREFUSED, "connection refused")                                      \
    XX(ECONNRESET, "connection reset by peer")                                  \
    XX(EDESTADDRREQ, "destination address required")                            \
    XX(EEXIST, "file already exists")                                           \
    XX(EFAULT, "bad address in system call argument")                           \
    XX(EHOSTUNREACH, "host is unreachable")                                     \
    XX(EINTR, "interrupted system call")                                        \
    XX(EINVAL, "invalid argument")                                              \
    XX(EIO, "i/o error")                                                        \
    XX(EISCONN, "socket is already connected")                                  \
    XX(EISDIR, "illegal operation on a directory")                              \
    XX(ELOOP, "too many symbolic links encountered")                            \
    XX(EMFILE, "too many open files")                                           \
    XX(EMSGSIZE, "message too long")                                            \
    XX(ENAMETOOLONG, "name too long")                                           \
    XX(ENETDOWN, "network is down")                                             \
    XX(ENETUNREACH, "network is unreachable")                                   \
    XX(ENFILE, "file table overflow")                                           \
    XX(ENOBUFS, "no buffer space available")                                    \
    XX(ENODEV, "no such device")                                                \
    XX(ENOENT, "no such file or directory")                                     \
    XX(ENOMEM, "not enough memory")                                             \
    XX(ENONET, "machine is not on the network")                                 \
    XX(ENOSPC, "no space left on device")                                       \
    XX(ENOSYS, "function not implemented")                                      \
    XX(ENOTCONN, "socket is not connected")                                     \
    XX(ENOTDIR, "not a directory")                                              \
    XX(ENOTEMPTY, "directory not empty")                                        \
    XX(ENOTSOCK, "socket operation on non-socket")                              \
    XX(ENOTSUP, "operation not supported on socket")                            \
    XX(EPERM, "operation not permitted")                                        \
    XX(EPIPE, "broken pipe")                                                    \
    XX(EPROTO, "protocol error")                                                \
    XX(EPROTONOSUPPORT, "protocol not supported")                               \
    XX(EPROTOTYPE, "protocol wrong type for socket")                            \
    XX(EROFS, "read-only file system")                                          \
    XX(ESHUTDOWN, "cannot send after transport endpoint shutdown")              \
    XX(ESPIPE, "invalid seek")                                                  \
    XX(ESRCH, "no such process")                                                \
    XX(ETIMEDOUT, "connection timed out")                                       \
    XX(EXDEV, "cross-device link not permitted")                                \
    XX(UNKNOWN, "unknown error")                                                \
    XX(EOF, "end of file")                                                      \
  
  #define UV_HANDLE_TYPE_MAP(XX)                                                \
    XX(ASYNC, async)                                                            \
    XX(CHECK, check)                                                            \
    XX(FS_EVENT, fs_event)                                                      \
    XX(FS_POLL, fs_poll)                                                        \
    XX(HANDLE, handle)                                                          \
    XX(IDLE, idle)                                                              \
    XX(NAMED_PIPE, pipe)                                                        \
    XX(POLL, poll)                                                              \
    XX(PREPARE, prepare)                                                        \
    XX(PROCESS, process)                                                        \
    XX(STREAM, stream)                                                          \
    XX(TCP, tcp)                                                                \
    XX(TIMER, timer)                                                            \
    XX(TTY, tty)                                                                \
    XX(UDP, udp)                                                                \
    XX(SIGNAL, signal)                                                          \
  
  #define UV_REQ_TYPE_MAP(XX)                                                   \
    XX(REQ, req)                                                                \
    XX(CONNECT, connect)                                                        \
    XX(WRITE, write)                                                            \
    XX(SHUTDOWN, shutdown)                                                      \
    XX(UDP_SEND, udp_send)                                                      \
    XX(FS, fs)                                                                  \
    XX(WORK, work)                                                              \
    XX(GETADDRINFO, getaddrinfo)                                                \
  
  typedef enum {
  #define XX(code, _) UV_ ## code = UV__ ## code,
    UV_ERRNO_MAP(XX)
  #undef XX
    UV_ERRNO_MAX = UV__EOF - 1
  } uv_errno_t;
  
  typedef enum {
    UV_UNKNOWN_HANDLE = 0,
  #define XX(uc, lc) UV_##uc,
    UV_HANDLE_TYPE_MAP(XX)
  #undef XX
    UV_FILE,
    UV_HANDLE_TYPE_MAX
  } uv_handle_type;
  
  typedef enum {
    UV_UNKNOWN_REQ = 0,
  #define XX(uc, lc) UV_##uc,
    UV_REQ_TYPE_MAP(XX)
  #undef XX
    UV_REQ_TYPE_PRIVATE
    UV_REQ_TYPE_MAX
  } uv_req_type;
  
  
  /* Handle types. */
  typedef struct uv_loop_s uv_loop_t;
  typedef struct uv_handle_s uv_handle_t;
  typedef struct uv_stream_s uv_stream_t;
  typedef struct uv_tcp_s uv_tcp_t;
  typedef struct uv_udp_s uv_udp_t;
  typedef struct uv_pipe_s uv_pipe_t;
  typedef struct uv_tty_s uv_tty_t;
  typedef struct uv_poll_s uv_poll_t;
  typedef struct uv_timer_s uv_timer_t;
  typedef struct uv_prepare_s uv_prepare_t;
  typedef struct uv_check_s uv_check_t;
  typedef struct uv_idle_s uv_idle_t;
  typedef struct uv_async_s uv_async_t;
  typedef struct uv_process_s uv_process_t;
  typedef struct uv_fs_event_s uv_fs_event_t;
  typedef struct uv_fs_poll_s uv_fs_poll_t;
  typedef struct uv_signal_s uv_signal_t;
  
  /* Request types. */
  typedef struct uv_req_s uv_req_t;
  typedef struct uv_getaddrinfo_s uv_getaddrinfo_t;
  typedef struct uv_shutdown_s uv_shutdown_t;
  typedef struct uv_write_s uv_write_t;
  typedef struct uv_connect_s uv_connect_t;
  typedef struct uv_udp_send_s uv_udp_send_t;
  typedef struct uv_fs_s uv_fs_t;
  typedef struct uv_work_s uv_work_t;
  
  /* None of the above. */
  typedef struct uv_cpu_info_s uv_cpu_info_t;
  typedef struct uv_interface_address_s uv_interface_address_t;
  
  
  typedef enum {
    UV_RUN_DEFAULT = 0,
    UV_RUN_ONCE,
    UV_RUN_NOWAIT
  } uv_run_mode;
  
  
  /*
   * Returns the libuv version packed into a single integer. 8 bits are used for
   * each component, with the patch number stored in the 8 least significant
   * bits. E.g. for libuv 1.2.3 this would return 0x010203.
   */
  UV_EXTERN unsigned int uv_version(void);
  
  /*
   * Returns the libuv version number as a string. For non-release versions
   * "-pre" is appended, so the version number could be "1.2.3-pre".
   */
  UV_EXTERN const char* uv_version_string(void);
  
  
  /*
   * This function must be called before any other functions in libuv.
   *
   * All functions besides uv_run() are non-blocking.
   *
   * All callbacks in libuv are made asynchronously. That is they are never
   * made by the function that takes them as a parameter.
   */
  UV_EXTERN uv_loop_t* uv_loop_new(void);
  UV_EXTERN void uv_loop_delete(uv_loop_t*);
  
  /*
   * Returns the default loop.
   */
  UV_EXTERN uv_loop_t* uv_default_loop(void);
  
  /*
   * This function runs the event loop. It will act differently depending on the
   * specified mode:
   *  - UV_RUN_DEFAULT: Runs the event loop until the reference count drops to
   *    zero. Always returns zero.
   *  - UV_RUN_ONCE: Poll for new events once. Note that this function blocks if
   *    there are no pending events. Returns zero when done (no active handles
   *    or requests left), or non-zero if more events are expected (meaning you
   *    should run the event loop again sometime in the future).
   *  - UV_RUN_NOWAIT: Poll for new events once but don't block if there are no
   *    pending events.
   */
  UV_EXTERN int uv_run(uv_loop_t*, uv_run_mode mode);
  
  /*
   * This function will stop the event loop by forcing uv_run to end
   * as soon as possible, but not sooner than the next loop iteration.
   * If this function was called before blocking for i/o, the loop won't
   * block for i/o on this iteration.
   */
  UV_EXTERN void uv_stop(uv_loop_t*);
  
  /*
   * Manually modify the event loop's reference count. Useful if the user wants
   * to have a handle or timeout that doesn't keep the loop alive.
   */
  UV_EXTERN void uv_ref(uv_handle_t*);
  UV_EXTERN void uv_unref(uv_handle_t*);
  UV_EXTERN int uv_has_ref(const uv_handle_t*);
  
  /*
   * Update the event loop's concept of "now". Libuv caches the current time
   * at the start of the event loop tick in order to reduce the number of
   * time-related system calls.
   *
   * You won't normally need to call this function unless you have callbacks
   * that block the event loop for longer periods of time, where "longer" is
   * somewhat subjective but probably on the order of a millisecond or more.
   */
  UV_EXTERN void uv_update_time(uv_loop_t*);
  
  /*
   * Return the current timestamp in milliseconds. The timestamp is cached at
   * the start of the event loop tick, see |uv_update_time()| for details and
   * rationale.
   *
   * The timestamp increases monotonically from some arbitrary point in time.
   * Don't make assumptions about the starting point, you will only get
   * disappointed.
   *
   * Use uv_hrtime() if you need sub-milliseond granularity.
   */
  UV_EXTERN uint64_t uv_now(uv_loop_t*);
  
  /*
   * Get backend file descriptor. Only kqueue, epoll and event ports are
   * supported.
   *
   * This can be used in conjunction with `uv_run(loop, UV_RUN_NOWAIT)` to
   * poll in one thread and run the event loop's event callbacks in another.
   *
   * Useful for embedding libuv's event loop in another event loop.
   * See test/test-embed.c for an example.
   *
   * Note that embedding a kqueue fd in another kqueue pollset doesn't work on
   * all platforms. It's not an error to add the fd but it never generates
   * events.
   */
  UV_EXTERN int uv_backend_fd(const uv_loop_t*);
  
  /*
   * Get the poll timeout. The return value is in milliseconds, or -1 for no
   * timeout.
   */
  UV_EXTERN int uv_backend_timeout(const uv_loop_t*);
  
  
  /*
   * Should return a buffer that libuv can use to read data into.
   *
   * `suggested_size` is a hint. Returning a buffer that is smaller is perfectly
   * okay as long as `buf.len > 0`.
   */
  typedef uv_buf_t (*uv_alloc_cb)(uv_handle_t* handle, size_t suggested_size);
  
  /*
   * `nread` is > 0 if there is data available, 0 if libuv is done reading for
   * now, or < 0 on error.
   *
   * The callee is responsible for closing the stream when an error happens.
   * Trying to read from the stream again is undefined.
   *
   * The callee is responsible for freeing the buffer, libuv does not reuse it.
   * The buffer may be a null buffer (where buf.base=NULL and buf.len=0) on EOF
   * or error.
   */
  typedef void (*uv_read_cb)(uv_stream_t* stream, ssize_t nread, uv_buf_t buf);
  
  /*
   * Just like the uv_read_cb except that if the pending parameter is true
   * then you can use uv_accept() to pull the new handle into the process.
   * If no handle is pending then pending will be UV_UNKNOWN_HANDLE.
   */
  typedef void (*uv_read2_cb)(uv_pipe_t* pipe, ssize_t nread, uv_buf_t buf,
      uv_handle_type pending);
  
  typedef void (*uv_write_cb)(uv_write_t* req, int status);
  typedef void (*uv_connect_cb)(uv_connect_t* req, int status);
  typedef void (*uv_shutdown_cb)(uv_shutdown_t* req, int status);
  typedef void (*uv_connection_cb)(uv_stream_t* server, int status);
  typedef void (*uv_close_cb)(uv_handle_t* handle);
  typedef void (*uv_poll_cb)(uv_poll_t* handle, int status, int events);
  typedef void (*uv_timer_cb)(uv_timer_t* handle, int status);
  /* TODO: do these really need a status argument? */
  typedef void (*uv_async_cb)(uv_async_t* handle, int status);
  typedef void (*uv_prepare_cb)(uv_prepare_t* handle, int status);
  typedef void (*uv_check_cb)(uv_check_t* handle, int status);
  typedef void (*uv_idle_cb)(uv_idle_t* handle, int status);
  typedef void (*uv_exit_cb)(uv_process_t*, int exit_status, int term_signal);
  typedef void (*uv_walk_cb)(uv_handle_t* handle, void* arg);
  typedef void (*uv_fs_cb)(uv_fs_t* req);
  typedef void (*uv_work_cb)(uv_work_t* req);
  typedef void (*uv_after_work_cb)(uv_work_t* req, int status);
  typedef void (*uv_getaddrinfo_cb)(uv_getaddrinfo_t* req,
                                    int status,
                                    struct addrinfo* res);
  
  typedef struct {
    long tv_sec;
    long tv_nsec;
  } uv_timespec_t;
  
  
  typedef struct {
    uint64_t st_dev;
    uint64_t st_mode;
    uint64_t st_nlink;
    uint64_t st_uid;
    uint64_t st_gid;
    uint64_t st_rdev;
    uint64_t st_ino;
    uint64_t st_size;
    uint64_t st_blksize;
    uint64_t st_blocks;
    uint64_t st_flags;
    uint64_t st_gen;
    uv_timespec_t st_atim;
    uv_timespec_t st_mtim;
    uv_timespec_t st_ctim;
    uv_timespec_t st_birthtim;
  } uv_stat_t;
  
  
  /*
  * This will be called repeatedly after the uv_fs_event_t is initialized.
  * If uv_fs_event_t was initialized with a directory the filename parameter
  * will be a relative path to a file contained in the directory.
  * The events parameter is an ORed mask of enum uv_fs_event elements.
  */
  typedef void (*uv_fs_event_cb)(uv_fs_event_t* handle, const char* filename,
      int events, int status);
  
  typedef void (*uv_fs_poll_cb)(uv_fs_poll_t* handle,
                                int status,
                                const uv_stat_t* prev,
                                const uv_stat_t* curr);
  
  typedef void (*uv_signal_cb)(uv_signal_t* handle, int signum);
  
  
  typedef enum {
    UV_LEAVE_GROUP = 0,
    UV_JOIN_GROUP
  } uv_membership;
  
  
  /*
   * Most functions return 0 on success or an error code < 0 on failure.
   */
  UV_EXTERN const char* uv_strerror(int err);
  UV_EXTERN const char* uv_err_name(int err);
  
  
  #define UV_REQ_FIELDS                                                         \
    /* public */                                                                \
    void* data;                                                                 \
    /* read-only */                                                             \
    uv_req_type type;                                                           \
    /* private */                                                               \
    void* active_queue[2];                                                      \
    UV_REQ_PRIVATE_FIELDS                                                       \
  
  /* Abstract base class of all requests. */
  struct uv_req_s {
    UV_REQ_FIELDS
  };
  
  
  /* Platform-specific request types */
  UV_PRIVATE_REQ_TYPES
  
  
  /*
   * uv_shutdown_t is a subclass of uv_req_t
   *
   * Shutdown the outgoing (write) side of a duplex stream. It waits for
   * pending write requests to complete. The handle should refer to a
   * initialized stream. req should be an uninitialized shutdown request
   * struct. The cb is called after shutdown is complete.
   */
  UV_EXTERN int uv_shutdown(uv_shutdown_t* req, uv_stream_t* handle,
      uv_shutdown_cb cb);
  
  struct uv_shutdown_s {
    UV_REQ_FIELDS
    uv_stream_t* handle;
    uv_shutdown_cb cb;
    UV_SHUTDOWN_PRIVATE_FIELDS
  };
  
  
  #define UV_HANDLE_FIELDS                                                      \
    /* public */                                                                \
    uv_close_cb close_cb;                                                       \
    void* data;                                                                 \
    /* read-only */                                                             \
    uv_loop_t* loop;                                                            \
    uv_handle_type type;                                                        \
    /* private */                                                               \
    void* handle_queue[2];                                                      \
    UV_HANDLE_PRIVATE_FIELDS                                                    \
  
  /* The abstract base class of all handles.  */
  struct uv_handle_s {
    UV_HANDLE_FIELDS
  };
  
  /*
   * Returns size of various handle types, useful for FFI
   * bindings to allocate correct memory without copying struct
   * definitions
   */
  UV_EXTERN size_t uv_handle_size(uv_handle_type type);
  
  /*
   * Returns size of request types, useful for dynamic lookup with FFI
   */
  UV_EXTERN size_t uv_req_size(uv_req_type type);
  
  /*
   * Returns 1 if the prepare/check/idle/timer handle has been started, 0
   * otherwise. For other handle types this always returns 1.
   */
  UV_EXTERN int uv_is_active(const uv_handle_t* handle);
  
  /*
   * Walk the list of open handles.
   */
  UV_EXTERN void uv_walk(uv_loop_t* loop, uv_walk_cb walk_cb, void* arg);
  
  
  /*
   * Request handle to be closed. close_cb will be called asynchronously after
   * this call. This MUST be called on each handle before memory is released.
   *
   * Note that handles that wrap file descriptors are closed immediately but
   * close_cb will still be deferred to the next iteration of the event loop.
   * It gives you a chance to free up any resources associated with the handle.
   *
   * In-progress requests, like uv_connect_t or uv_write_t, are cancelled and
   * have their callbacks called asynchronously with status=UV_ECANCELED.
   */
  UV_EXTERN void uv_close(uv_handle_t* handle, uv_close_cb close_cb);
  
  
  /*
   * Constructor for uv_buf_t.
   * Due to platform differences the user cannot rely on the ordering of the
   * base and len members of the uv_buf_t struct. The user is responsible for
   * freeing base after the uv_buf_t is done. Return struct passed by value.
   */
  UV_EXTERN uv_buf_t uv_buf_init(char* base, unsigned int len);
  
  
  /*
   * Utility function. Copies up to `size` characters from `src` to `dst`
   * and ensures that `dst` is properly NUL terminated unless `size` is zero.
   */
  UV_EXTERN size_t uv_strlcpy(char* dst, const char* src, size_t size);
  
  /*
   * Utility function. Appends `src` to `dst` and ensures that `dst` is
   * properly NUL terminated unless `size` is zero or `dst` does not
   * contain a NUL byte. `size` is the total length of `dst` so at most
   * `size - strlen(dst) - 1` characters will be copied from `src`.
   */
  UV_EXTERN size_t uv_strlcat(char* dst, const char* src, size_t size);
  
  
  #define UV_STREAM_FIELDS                                                      \
    /* number of bytes queued for writing */                                    \
    size_t write_queue_size;                                                    \
    uv_alloc_cb alloc_cb;                                                       \
    uv_read_cb read_cb;                                                         \
    uv_read2_cb read2_cb;                                                       \
    /* private */                                                               \
    UV_STREAM_PRIVATE_FIELDS
  
  /*
   * uv_stream_t is a subclass of uv_handle_t
   *
   * uv_stream is an abstract class.
   *
   * uv_stream_t is the parent class of uv_tcp_t, uv_pipe_t, uv_tty_t, and
   * soon uv_file_t.
   */
  struct uv_stream_s {
    UV_HANDLE_FIELDS
    UV_STREAM_FIELDS
  };
  
  UV_EXTERN int uv_listen(uv_stream_t* stream, int backlog, uv_connection_cb cb);
  
  /*
   * This call is used in conjunction with uv_listen() to accept incoming
   * connections. Call uv_accept after receiving a uv_connection_cb to accept
   * the connection. Before calling uv_accept use uv_*_init() must be
   * called on the client. Non-zero return value indicates an error.
   *
   * When the uv_connection_cb is called it is guaranteed that uv_accept will
   * complete successfully the first time. If you attempt to use it more than
   * once, it may fail. It is suggested to only call uv_accept once per
   * uv_connection_cb call.
   */
  UV_EXTERN int uv_accept(uv_stream_t* server, uv_stream_t* client);
  
  /*
   * Read data from an incoming stream. The callback will be made several
   * times until there is no more data to read or uv_read_stop is called.
   * When we've reached EOF nread will be set to UV_EOF.
   *
   * When nread < 0, the buf parameter might not point to a valid buffer;
   * in that case buf.len and buf.base are both set to 0.
   *
   * Note that nread might also be 0, which does *not* indicate an error or
   * eof; it happens when libuv requested a buffer through the alloc callback
   * but then decided that it didn't need that buffer.
   */
  UV_EXTERN int uv_read_start(uv_stream_t*, uv_alloc_cb alloc_cb,
      uv_read_cb read_cb);
  
  UV_EXTERN int uv_read_stop(uv_stream_t*);
  
  /*
   * Extended read methods for receiving handles over a pipe. The pipe must be
   * initialized with ipc == 1.
   */
  UV_EXTERN int uv_read2_start(uv_stream_t*, uv_alloc_cb alloc_cb,
      uv_read2_cb read_cb);
  
  
  /*
   * Write data to stream. Buffers are written in order. Example:
   *
   *   uv_buf_t a[] = {
   *     { .base = "1", .len = 1 },
   *     { .base = "2", .len = 1 }
   *   };
   *
   *   uv_buf_t b[] = {
   *     { .base = "3", .len = 1 },
   *     { .base = "4", .len = 1 }
   *   };
   *
   *   uv_write_t req1;
   *   uv_write_t req2;
   *
   *   // writes "1234"
   *   uv_write(&req1, stream, a, 2);
   *   uv_write(&req2, stream, b, 2);
   *
   */
  UV_EXTERN int uv_write(uv_write_t* req, uv_stream_t* handle,
      uv_buf_t bufs[], int bufcnt, uv_write_cb cb);
  
  /*
   * Extended write function for sending handles over a pipe. The pipe must be
   * initialized with ipc == 1.
   * send_handle must be a TCP socket or pipe, which is a server or a connection
   * (listening or connected state).  Bound sockets or pipes will be assumed to
   * be servers.
   */
  UV_EXTERN int uv_write2(uv_write_t* req, uv_stream_t* handle, uv_buf_t bufs[],
      int bufcnt, uv_stream_t* send_handle, uv_write_cb cb);
  
  /* uv_write_t is a subclass of uv_req_t */
  struct uv_write_s {
    UV_REQ_FIELDS
    uv_write_cb cb;
    uv_stream_t* send_handle;
    uv_stream_t* handle;
    UV_WRITE_PRIVATE_FIELDS
  };
  
  
  /*
   * Used to determine whether a stream is readable or writable.
   */
  UV_EXTERN int uv_is_readable(const uv_stream_t* handle);
  UV_EXTERN int uv_is_writable(const uv_stream_t* handle);
  
  
  /*
   * Enable or disable blocking mode for a stream.
   *
   * When blocking mode is enabled all writes complete synchronously. The
   * interface remains unchanged otherwise, e.g. completion or failure of the
   * operation will still be reported through a callback which is made
   * asychronously.
   *
   * Relying too much on this API is not recommended. It is likely to change
   * significantly in the future.
   *
   * On windows this currently works only for uv_pipe_t instances. On unix it
   * works for tcp, pipe and tty instances. Be aware that changing the blocking
   * mode on unix sets or clears the O_NONBLOCK bit. If you are sharing a handle
   * with another process, the other process is affected by the change too,
   * which can lead to unexpected results.
   *
   * Also libuv currently makes no ordering guarantee when the blocking mode
   * is changed after write requests have already been submitted. Therefore it is
   * recommended to set the blocking mode immediately after opening or creating
   * the stream.
   */
  UV_EXTERN int uv_stream_set_blocking(uv_stream_t* handle, int blocking);
  
  
  /*
   * Used to determine whether a stream is closing or closed.
   *
   * N.B. is only valid between the initialization of the handle
   *      and the arrival of the close callback, and cannot be used
   *      to validate the handle.
   */
  UV_EXTERN int uv_is_closing(const uv_handle_t* handle);
  
  
  /*
   * uv_tcp_t is a subclass of uv_stream_t
   *
   * Represents a TCP stream or TCP server.
   */
  struct uv_tcp_s {
    UV_HANDLE_FIELDS
    UV_STREAM_FIELDS
    UV_TCP_PRIVATE_FIELDS
  };
  
  UV_EXTERN int uv_tcp_init(uv_loop_t*, uv_tcp_t* handle);
  
  /*
   * Opens an existing file descriptor or SOCKET as a tcp handle.
   */
  UV_EXTERN int uv_tcp_open(uv_tcp_t* handle, uv_os_sock_t sock);
  
  /* Enable/disable Nagle's algorithm. */
  UV_EXTERN int uv_tcp_nodelay(uv_tcp_t* handle, int enable);
  
  /*
   * Enable/disable TCP keep-alive.
   *
   * `delay` is the initial delay in seconds, ignored when `enable` is zero.
   */
  UV_EXTERN int uv_tcp_keepalive(uv_tcp_t* handle,
                                 int enable,
                                 unsigned int delay);
  
  /*
   * Enable/disable simultaneous asynchronous accept requests that are
   * queued by the operating system when listening for new tcp connections.
   * This setting is used to tune a tcp server for the desired performance.
   * Having simultaneous accepts can significantly improve the rate of
   * accepting connections (which is why it is enabled by default) but
   * may lead to uneven load distribution in multi-process setups.
   */
  UV_EXTERN int uv_tcp_simultaneous_accepts(uv_tcp_t* handle, int enable);
  
  UV_EXTERN int uv_tcp_bind(uv_tcp_t* handle, struct sockaddr_in);
  UV_EXTERN int uv_tcp_bind6(uv_tcp_t* handle, struct sockaddr_in6);
  UV_EXTERN int uv_tcp_getsockname(uv_tcp_t* handle, struct sockaddr* name,
      int* namelen);
  UV_EXTERN int uv_tcp_getpeername(uv_tcp_t* handle, struct sockaddr* name,
      int* namelen);
  
  /*
   * uv_tcp_connect, uv_tcp_connect6
   * These functions establish IPv4 and IPv6 TCP connections. Provide an
   * initialized TCP handle and an uninitialized uv_connect_t*. The callback
   * will be made when the connection is established.
   */
  UV_EXTERN int uv_tcp_connect(uv_connect_t* req, uv_tcp_t* handle,
      struct sockaddr_in address, uv_connect_cb cb);
  UV_EXTERN int uv_tcp_connect6(uv_connect_t* req, uv_tcp_t* handle,
      struct sockaddr_in6 address, uv_connect_cb cb);
  
  /* uv_connect_t is a subclass of uv_req_t */
  struct uv_connect_s {
    UV_REQ_FIELDS
    uv_connect_cb cb;
    uv_stream_t* handle;
    UV_CONNECT_PRIVATE_FIELDS
  };
  
  
  /*
   * UDP support.
   */
  
  enum uv_udp_flags {
    /* Disables dual stack mode. Used with uv_udp_bind6(). */
    UV_UDP_IPV6ONLY = 1,
    /*
     * Indicates message was truncated because read buffer was too small. The
     * remainder was discarded by the OS. Used in uv_udp_recv_cb.
     */
    UV_UDP_PARTIAL = 2
  };
  
  /*
   * Called after a uv_udp_send() or uv_udp_send6(). status 0 indicates
   * success otherwise error.
   */
  typedef void (*uv_udp_send_cb)(uv_udp_send_t* req, int status);
  
  /*
   * Callback that is invoked when a new UDP datagram is received.
   *
   *  handle  UDP handle.
   *  nread   Number of bytes that have been received.
   *          0 if there is no more data to read. You may
   *          discard or repurpose the read buffer.
   *          < 0 if a transmission error was detected.
   *  buf     uv_buf_t with the received data.
   *  addr    struct sockaddr_in or struct sockaddr_in6.
   *          Valid for the duration of the callback only.
   *  flags   One or more OR'ed UV_UDP_* constants.
   *          Right now only UV_UDP_PARTIAL is used.
   */
  typedef void (*uv_udp_recv_cb)(uv_udp_t* handle, ssize_t nread, uv_buf_t buf,
      struct sockaddr* addr, unsigned flags);
  
  /* uv_udp_t is a subclass of uv_handle_t */
  struct uv_udp_s {
    UV_HANDLE_FIELDS
    UV_UDP_PRIVATE_FIELDS
  };
  
  /* uv_udp_send_t is a subclass of uv_req_t */
  struct uv_udp_send_s {
    UV_REQ_FIELDS
    uv_udp_t* handle;
    uv_udp_send_cb cb;
    UV_UDP_SEND_PRIVATE_FIELDS
  };
  
  /*
   * Initialize a new UDP handle. The actual socket is created lazily.
   * Returns 0 on success.
   */
  UV_EXTERN int uv_udp_init(uv_loop_t*, uv_udp_t* handle);
  
  /*
   * Opens an existing file descriptor or SOCKET as a udp handle.
   *
   * Unix only:
   *  The only requirement of the sock argument is that it follows the
   *  datagram contract (works in unconnected mode, supports sendmsg()/recvmsg(),
   *  etc.). In other words, other datagram-type sockets like raw sockets or
   *  netlink sockets can also be passed to this function.
   */
  UV_EXTERN int uv_udp_open(uv_udp_t* handle, uv_os_sock_t sock);
  
  /*
   * Bind to a IPv4 address and port.
   *
   * Arguments:
   *  handle    UDP handle. Should have been initialized with `uv_udp_init`.
   *  addr      struct sockaddr_in with the address and port to bind to.
   *  flags     Unused.
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_bind(uv_udp_t* handle, struct sockaddr_in addr,
      unsigned flags);
  
  /*
   * Bind to a IPv6 address and port.
   *
   * Arguments:
   *  handle    UDP handle. Should have been initialized with `uv_udp_init`.
   *  addr      struct sockaddr_in with the address and port to bind to.
   *  flags     Should be 0 or UV_UDP_IPV6ONLY.
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_bind6(uv_udp_t* handle, struct sockaddr_in6 addr,
      unsigned flags);
  
  UV_EXTERN int uv_udp_getsockname(uv_udp_t* handle, struct sockaddr* name,
      int* namelen);
  
  /*
   * Set membership for a multicast address
   *
   * Arguments:
   *  handle              UDP handle. Should have been initialized with
   *                      `uv_udp_init`.
   *  multicast_addr      multicast address to set membership for
   *  interface_addr      interface address
   *  membership          Should be UV_JOIN_GROUP or UV_LEAVE_GROUP
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_set_membership(uv_udp_t* handle,
      const char* multicast_addr, const char* interface_addr,
      uv_membership membership);
  
  /*
   * Set IP multicast loop flag. Makes multicast packets loop back to
   * local sockets.
   *
   * Arguments:
   *  handle              UDP handle. Should have been initialized with
   *                      `uv_udp_init`.
   *  on                  1 for on, 0 for off
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_set_multicast_loop(uv_udp_t* handle, int on);
  
  /*
   * Set the multicast ttl
   *
   * Arguments:
   *  handle              UDP handle. Should have been initialized with
   *                      `uv_udp_init`.
   *  ttl                 1 through 255
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_set_multicast_ttl(uv_udp_t* handle, int ttl);
  
  /*
   * Set broadcast on or off
   *
   * Arguments:
   *  handle              UDP handle. Should have been initialized with
   *                      `uv_udp_init`.
   *  on                  1 for on, 0 for off
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_set_broadcast(uv_udp_t* handle, int on);
  
  /*
   * Set the time to live
   *
   * Arguments:
   *  handle              UDP handle. Should have been initialized with
   *                      `uv_udp_init`.
   *  ttl                 1 through 255
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_set_ttl(uv_udp_t* handle, int ttl);
  
  /*
   * Send data. If the socket has not previously been bound with `uv_udp_bind`
   * or `uv_udp_bind6`, it is bound to 0.0.0.0 (the "all interfaces" address)
   * and a random port number.
   *
   * Arguments:
   *  req       UDP request handle. Need not be initialized.
   *  handle    UDP handle. Should have been initialized with `uv_udp_init`.
   *  bufs      List of buffers to send.
   *  bufcnt    Number of buffers in `bufs`.
   *  addr      Address of the remote peer. See `uv_ip4_addr`.
   *  send_cb   Callback to invoke when the data has been sent out.
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_send(uv_udp_send_t* req, uv_udp_t* handle,
      uv_buf_t bufs[], int bufcnt, struct sockaddr_in addr,
      uv_udp_send_cb send_cb);
  
  /*
   * Send data. If the socket has not previously been bound with `uv_udp_bind6`,
   * it is bound to ::0 (the "all interfaces" address) and a random port number.
   *
   * Arguments:
   *  req       UDP request handle. Need not be initialized.
   *  handle    UDP handle. Should have been initialized with `uv_udp_init`.
   *  bufs      List of buffers to send.
   *  bufcnt    Number of buffers in `bufs`.
   *  addr      Address of the remote peer. See `uv_ip6_addr`.
   *  send_cb   Callback to invoke when the data has been sent out.
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_send6(uv_udp_send_t* req, uv_udp_t* handle,
      uv_buf_t bufs[], int bufcnt, struct sockaddr_in6 addr,
      uv_udp_send_cb send_cb);
  
  /*
   * Receive data. If the socket has not previously been bound with `uv_udp_bind`
   * or `uv_udp_bind6`, it is bound to 0.0.0.0 (the "all interfaces" address)
   * and a random port number.
   *
   * Arguments:
   *  handle    UDP handle. Should have been initialized with `uv_udp_init`.
   *  alloc_cb  Callback to invoke when temporary storage is needed.
   *  recv_cb   Callback to invoke with received data.
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_recv_start(uv_udp_t* handle, uv_alloc_cb alloc_cb,
      uv_udp_recv_cb recv_cb);
  
  /*
   * Stop listening for incoming datagrams.
   *
   * Arguments:
   *  handle    UDP handle. Should have been initialized with `uv_udp_init`.
   *
   * Returns:
   *  0 on success, or an error code < 0 on failure.
   */
  UV_EXTERN int uv_udp_recv_stop(uv_udp_t* handle);
  
  
  /*
   * uv_tty_t is a subclass of uv_stream_t
   *
   * Representing a stream for the console.
   */
  struct uv_tty_s {
    UV_HANDLE_FIELDS
    UV_STREAM_FIELDS
    UV_TTY_PRIVATE_FIELDS
  };
  
  /*
   * Initialize a new TTY stream with the given file descriptor. Usually the
   * file descriptor will be
   *   0 = stdin
   *   1 = stdout
   *   2 = stderr
   * The last argument, readable, specifies if you plan on calling
   * uv_read_start with this stream. stdin is readable, stdout is not.
   *
   * TTY streams which are not readable have blocking writes.
   */
  UV_EXTERN int uv_tty_init(uv_loop_t*, uv_tty_t*, uv_file fd, int readable);
  
  /*
   * Set mode. 0 for normal, 1 for raw.
   */
  UV_EXTERN int uv_tty_set_mode(uv_tty_t*, int mode);
  
  /*
   * To be called when the program exits. Resets TTY settings to default
   * values for the next process to take over.
   */
  UV_EXTERN void uv_tty_reset_mode(void);
  
  /*
   * Gets the current Window size. On success zero is returned.
   */
  UV_EXTERN int uv_tty_get_winsize(uv_tty_t*, int* width, int* height);
  
  /*
   * Used to detect what type of stream should be used with a given file
   * descriptor. Usually this will be used during initialization to guess the
   * type of the stdio streams.
   * For isatty() functionality use this function and test for UV_TTY.
   */
  UV_EXTERN uv_handle_type uv_guess_handle(uv_file file);
  
  /*
   * uv_pipe_t is a subclass of uv_stream_t
   *
   * Representing a pipe stream or pipe server. On Windows this is a Named
   * Pipe. On Unix this is a UNIX domain socket.
   */
  struct uv_pipe_s {
    UV_HANDLE_FIELDS
    UV_STREAM_FIELDS
    int ipc; /* non-zero if this pipe is used for passing handles */
    UV_PIPE_PRIVATE_FIELDS
  };
  
  /*
   * Initialize a pipe. The last argument is a boolean to indicate if
   * this pipe will be used for handle passing between processes.
   */
  UV_EXTERN int uv_pipe_init(uv_loop_t*, uv_pipe_t* handle, int ipc);
  
  /*
   * Opens an existing file descriptor or HANDLE as a pipe.
   */
  UV_EXTERN int uv_pipe_open(uv_pipe_t*, uv_file file);
  
  UV_EXTERN int uv_pipe_bind(uv_pipe_t* handle, const char* name);
  
  UV_EXTERN void uv_pipe_connect(uv_connect_t* req, uv_pipe_t* handle,
      const char* name, uv_connect_cb cb);
  
  /*
   * This setting applies to Windows only.
   * Set the number of pending pipe instance handles when the pipe server
   * is waiting for connections.
   */
  UV_EXTERN void uv_pipe_pending_instances(uv_pipe_t* handle, int count);
  
  
  /*
   * uv_poll_t is a subclass of uv_handle_t.
   *
   * The uv_poll watcher is used to watch file descriptors for readability and
   * writability, similar to the purpose of poll(2).
   *
   * The purpose of uv_poll is to enable integrating external libraries that
   * rely on the event loop to signal it about the socket status changes, like
   * c-ares or libssh2. Using uv_poll_t for any other other purpose is not
   * recommended; uv_tcp_t, uv_udp_t, etc. provide an implementation that is
   * much faster and more scalable than what can be achieved with uv_poll_t,
   * especially on Windows.
   *
   * It is possible that uv_poll occasionally signals that a file descriptor is
   * readable or writable even when it isn't. The user should therefore always
   * be prepared to handle EAGAIN or equivalent when it attempts to read from or
   * write to the fd.
   *
   * It is not okay to have multiple active uv_poll watchers for the same socket.
   * This can cause libuv to busyloop or otherwise malfunction.
   *
   * The user should not close a file descriptor while it is being polled by an
   * active uv_poll watcher. This can cause the poll watcher to report an error,
   * but it might also start polling another socket. However the fd can be safely
   * closed immediately after a call to uv_poll_stop() or uv_close().
   *
   * On windows only sockets can be polled with uv_poll. On unix any file
   * descriptor that would be accepted by poll(2) can be used with uv_poll.
   */
  struct uv_poll_s {
    UV_HANDLE_FIELDS
    uv_poll_cb poll_cb;
    UV_POLL_PRIVATE_FIELDS
  };
  
  enum uv_poll_event {
    UV_READABLE = 1,
    UV_WRITABLE = 2
  };
  
  /* Initialize the poll watcher using a file descriptor. */
  UV_EXTERN int uv_poll_init(uv_loop_t* loop, uv_poll_t* handle, int fd);
  
  /* Initialize the poll watcher using a socket descriptor. On unix this is */
  /* identical to uv_poll_init. On windows it takes a SOCKET handle. */
  UV_EXTERN int uv_poll_init_socket(uv_loop_t* loop, uv_poll_t* handle,
      uv_os_sock_t socket);
  
  /*
   * Starts polling the file descriptor. `events` is a bitmask consisting made up
   * of UV_READABLE and UV_WRITABLE. As soon as an event is detected the callback
   * will be called with `status` set to 0, and the detected events set en the
   * `events` field.
   *
   * If an error happens while polling status, `status` < 0 and corresponds
   * with one of the UV_E* error codes. The user should not close the socket
   * while uv_poll is active. If the user does that anyway, the callback *may*
   * be called reporting an error status, but this is not guaranteed.
   *
   * Calling uv_poll_start on an uv_poll watcher that is already active is fine.
   * Doing so will update the events mask that is being watched for.
   */
  UV_EXTERN int uv_poll_start(uv_poll_t* handle, int events, uv_poll_cb cb);
  
  /* Stops polling the file descriptor. */
  UV_EXTERN int uv_poll_stop(uv_poll_t* handle);
  
  
  /*
   * uv_prepare_t is a subclass of uv_handle_t.
   *
   * Every active prepare handle gets its callback called exactly once per loop
   * iteration, just before the system blocks to wait for completed i/o.
   */
  struct uv_prepare_s {
    UV_HANDLE_FIELDS
    UV_PREPARE_PRIVATE_FIELDS
  };
  
  UV_EXTERN int uv_prepare_init(uv_loop_t*, uv_prepare_t* prepare);
  
  UV_EXTERN int uv_prepare_start(uv_prepare_t* prepare, uv_prepare_cb cb);
  
  UV_EXTERN int uv_prepare_stop(uv_prepare_t* prepare);
  
  
  /*
   * uv_check_t is a subclass of uv_handle_t.
   *
   * Every active check handle gets its callback called exactly once per loop
   * iteration, just after the system returns from blocking.
   */
  struct uv_check_s {
    UV_HANDLE_FIELDS
    UV_CHECK_PRIVATE_FIELDS
  };
  
  UV_EXTERN int uv_check_init(uv_loop_t*, uv_check_t* check);
  
  UV_EXTERN int uv_check_start(uv_check_t* check, uv_check_cb cb);
  
  UV_EXTERN int uv_check_stop(uv_check_t* check);
  
  
  /*
   * uv_idle_t is a subclass of uv_handle_t.
   *
   * Every active idle handle gets its callback called repeatedly until it is
   * stopped. This happens after all other types of callbacks are processed.
   * When there are multiple "idle" handles active, their callbacks are called
   * in turn.
   */
  struct uv_idle_s {
    UV_HANDLE_FIELDS
    UV_IDLE_PRIVATE_FIELDS
  };
  
  UV_EXTERN int uv_idle_init(uv_loop_t*, uv_idle_t* idle);
  
  UV_EXTERN int uv_idle_start(uv_idle_t* idle, uv_idle_cb cb);
  
  UV_EXTERN int uv_idle_stop(uv_idle_t* idle);
  
  
  /*
   * uv_async_t is a subclass of uv_handle_t.
   *
   * uv_async_send wakes up the event loop and calls the async handle's callback.
   * There is no guarantee that every uv_async_send call leads to exactly one
   * invocation of the callback; the only guarantee is that the callback function
   * is called at least once after the call to async_send. Unlike all other
   * libuv functions, uv_async_send can be called from another thread.
   */
  struct uv_async_s {
    UV_HANDLE_FIELDS
    UV_ASYNC_PRIVATE_FIELDS
  };
  
  UV_EXTERN int uv_async_init(uv_loop_t*, uv_async_t* async,
      uv_async_cb async_cb);
  
  /*
   * This can be called from other threads to wake up a libuv thread.
   *
   * libuv is single threaded at the moment.
   */
  UV_EXTERN int uv_async_send(uv_async_t* async);
  
  
  /*
   * uv_timer_t is a subclass of uv_handle_t.
   *
   * Used to get woken up at a specified time in the future.
   */
  struct uv_timer_s {
    UV_HANDLE_FIELDS
    UV_TIMER_PRIVATE_FIELDS
  };
  
  UV_EXTERN int uv_timer_init(uv_loop_t*, uv_timer_t* handle);
  
  /*
   * Start the timer. `timeout` and `repeat` are in milliseconds.
   *
   * If timeout is zero, the callback fires on the next tick of the event loop.
   *
   * If repeat is non-zero, the callback fires first after timeout milliseconds
   * and then repeatedly after repeat milliseconds.
   */
  UV_EXTERN int uv_timer_start(uv_timer_t* handle,
                               uv_timer_cb cb,
                               uint64_t timeout,
                               uint64_t repeat);
  
  UV_EXTERN int uv_timer_stop(uv_timer_t* handle);
  
  /*
   * Stop the timer, and if it is repeating restart it using the repeat value
   * as the timeout. If the timer has never been started before it returns
   * UV_EINVAL.
   */
  UV_EXTERN int uv_timer_again(uv_timer_t* handle);
  
  /*
   * Set the repeat value in milliseconds. Note that if the repeat value is set
   * from a timer callback it does not immediately take effect. If the timer was
   * non-repeating before, it will have been stopped. If it was repeating, then
   * the old repeat value will have been used to schedule the next timeout.
   */
  UV_EXTERN void uv_timer_set_repeat(uv_timer_t* handle, uint64_t repeat);
  
  UV_EXTERN uint64_t uv_timer_get_repeat(const uv_timer_t* handle);
  
  
  /*
   * uv_getaddrinfo_t is a subclass of uv_req_t
   *
   * Request object for uv_getaddrinfo.
   */
  struct uv_getaddrinfo_s {
    UV_REQ_FIELDS
    /* read-only */
    uv_loop_t* loop;
    UV_GETADDRINFO_PRIVATE_FIELDS
  };
  
  
  /*
   * Asynchronous getaddrinfo(3).
   *
   * Either node or service may be NULL but not both.
   *
   * hints is a pointer to a struct addrinfo with additional address type
   * constraints, or NULL. Consult `man -s 3 getaddrinfo` for details.
   *
   * Returns 0 on success or an error code < 0 on failure.
   *
   * If successful, your callback gets called sometime in the future with the
   * lookup result, which is either:
   *
   *  a) err == 0, the res argument points to a valid struct addrinfo, or
   *  b) err < 0, the res argument is NULL. See the UV_EAI_* constants.
   *
   * Call uv_freeaddrinfo() to free the addrinfo structure.
   */
  UV_EXTERN int uv_getaddrinfo(uv_loop_t* loop,
                               uv_getaddrinfo_t* req,
                               uv_getaddrinfo_cb getaddrinfo_cb,
                               const char* node,
                               const char* service,
                               const struct addrinfo* hints);
  
  /*
   * Free the struct addrinfo. Passing NULL is allowed and is a no-op.
   */
  UV_EXTERN void uv_freeaddrinfo(struct addrinfo* ai);
  
  
  /* uv_spawn() options */
  typedef enum {
    UV_IGNORE         = 0x00,
    UV_CREATE_PIPE    = 0x01,
    UV_INHERIT_FD     = 0x02,
    UV_INHERIT_STREAM = 0x04,
  
    /* When UV_CREATE_PIPE is specified, UV_READABLE_PIPE and UV_WRITABLE_PIPE
     * determine the direction of flow, from the child process' perspective. Both
     * flags may be specified to create a duplex data stream.
     */
    UV_READABLE_PIPE  = 0x10,
    UV_WRITABLE_PIPE  = 0x20
  } uv_stdio_flags;
  
  typedef struct uv_stdio_container_s {
    uv_stdio_flags flags;
  
    union {
      uv_stream_t* stream;
      int fd;
    } data;
  } uv_stdio_container_t;
  
  typedef struct uv_process_options_s {
    uv_exit_cb exit_cb; /* Called after the process exits. */
    const char* file; /* Path to program to execute. */
    /*
     * Command line arguments. args[0] should be the path to the program. On
     * Windows this uses CreateProcess which concatenates the arguments into a
     * string this can cause some strange errors. See the note at
     * windows_verbatim_arguments.
     */
    char** args;
    /*
     * This will be set as the environ variable in the subprocess. If this is
     * NULL then the parents environ will be used.
     */
    char** env;
    /*
     * If non-null this represents a directory the subprocess should execute
     * in. Stands for current working directory.
     */
    char* cwd;
    /*
     * Various flags that control how uv_spawn() behaves. See the definition of
     * `enum uv_process_flags` below.
     */
    unsigned int flags;
    /*
     * The `stdio` field points to an array of uv_stdio_container_t structs that
     * describe the file descriptors that will be made available to the child
     * process. The convention is that stdio[0] points to stdin, fd 1 is used for
     * stdout, and fd 2 is stderr.
     *
     * Note that on windows file descriptors greater than 2 are available to the
     * child process only if the child processes uses the MSVCRT runtime.
     */
    int stdio_count;
    uv_stdio_container_t* stdio;
    /*
     * Libuv can change the child process' user/group id. This happens only when
     * the appropriate bits are set in the flags fields. This is not supported on
     * windows; uv_spawn() will fail and set the error to UV_ENOTSUP.
     */
    uv_uid_t uid;
    uv_gid_t gid;
  } uv_process_options_t;
  
  /*
   * These are the flags that can be used for the uv_process_options.flags field.
   */
  enum uv_process_flags {
    /*
     * Set the child process' user id. The user id is supplied in the `uid` field
     * of the options struct. This does not work on windows; setting this flag
     * will cause uv_spawn() to fail.
     */
    UV_PROCESS_SETUID = (1 << 0),
    /*
     * Set the child process' group id. The user id is supplied in the `gid`
     * field of the options struct. This does not work on windows; setting this
     * flag will cause uv_spawn() to fail.
     */
    UV_PROCESS_SETGID = (1 << 1),
    /*
     * Do not wrap any arguments in quotes, or perform any other escaping, when
     * converting the argument list into a command line string. This option is
     * only meaningful on Windows systems. On unix it is silently ignored.
     */
    UV_PROCESS_WINDOWS_VERBATIM_ARGUMENTS = (1 << 2),
    /*
     * Spawn the child process in a detached state - this will make it a process
     * group leader, and will effectively enable the child to keep running after
     * the parent exits.  Note that the child process will still keep the
     * parent's event loop alive unless the parent process calls uv_unref() on
     * the child's process handle.
     */
    UV_PROCESS_DETACHED = (1 << 3),
    /*
     * Hide the subprocess console window that would normally be created. This
     * option is only meaningful on Windows systems. On unix it is silently
     * ignored.
     */
    UV_PROCESS_WINDOWS_HIDE = (1 << 4)
  };
  
  /*
   * uv_process_t is a subclass of uv_handle_t
   */
  struct uv_process_s {
    UV_HANDLE_FIELDS
    uv_exit_cb exit_cb;
    int pid;
    UV_PROCESS_PRIVATE_FIELDS
  };
  
  /* Initializes uv_process_t and starts the process. */
  UV_EXTERN int uv_spawn(uv_loop_t*, uv_process_t*,
      uv_process_options_t options);
  
  
  /*
   * Kills the process with the specified signal. The user must still
   * call uv_close on the process.
   */
  UV_EXTERN int uv_process_kill(uv_process_t*, int signum);
  
  
  /* Kills the process with the specified signal. */
  UV_EXTERN int uv_kill(int pid, int signum);
  
  
  /*
   * uv_work_t is a subclass of uv_req_t
   */
  struct uv_work_s {
    UV_REQ_FIELDS
    uv_loop_t* loop;
    uv_work_cb work_cb;
    uv_after_work_cb after_work_cb;
    UV_WORK_PRIVATE_FIELDS
  };
  
  /* Queues a work request to execute asynchronously on the thread pool. */
  UV_EXTERN int uv_queue_work(uv_loop_t* loop, uv_work_t* req,
      uv_work_cb work_cb, uv_after_work_cb after_work_cb);
  
  /* Cancel a pending request. Fails if the request is executing or has finished
   * executing.
   *
   * Returns 0 on success, or an error code < 0 on failure.
   *
   * Only cancellation of uv_fs_t, uv_getaddrinfo_t and uv_work_t requests is
   * currently supported.
   *
   * Cancelled requests have their callbacks invoked some time in the future.
   * It's _not_ safe to free the memory associated with the request until your
   * callback is called.
   *
   * Here is how cancellation is reported to your callback:
   *
   * - A uv_fs_t request has its req->result field set to UV_ECANCELED.
   *
   * - A uv_work_t or uv_getaddrinfo_t request has its callback invoked with
   *   status == UV_ECANCELED.
   *
   * This function is currently only implemented on UNIX platforms. On Windows,
   * it always returns UV_ENOSYS.
   */
  UV_EXTERN int uv_cancel(uv_req_t* req);
  
  
  struct uv_cpu_info_s {
    char* model;
    int speed;
    struct uv_cpu_times_s {
      uint64_t user;
      uint64_t nice;
      uint64_t sys;
      uint64_t idle;
      uint64_t irq;
    } cpu_times;
  };
  
  struct uv_interface_address_s {
    char* name;
    int is_internal;
    union {
      struct sockaddr_in address4;
      struct sockaddr_in6 address6;
    } address;
    union {
      struct sockaddr_in netmask4;
      struct sockaddr_in6 netmask6;
    } netmask;
  };
  
  UV_EXTERN char** uv_setup_args(int argc, char** argv);
  UV_EXTERN int uv_get_process_title(char* buffer, size_t size);
  UV_EXTERN int uv_set_process_title(const char* title);
  UV_EXTERN int uv_resident_set_memory(size_t* rss);
  UV_EXTERN int uv_uptime(double* uptime);
  
  /*
   * This allocates cpu_infos array, and sets count.  The array
   * is freed using uv_free_cpu_info().
   */
  UV_EXTERN int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count);
  UV_EXTERN void uv_free_cpu_info(uv_cpu_info_t* cpu_infos, int count);
  
  /*
   * This allocates addresses array, and sets count.  The array
   * is freed using uv_free_interface_addresses().
   */
  UV_EXTERN int uv_interface_addresses(uv_interface_address_t** addresses,
    int* count);
  UV_EXTERN void uv_free_interface_addresses(uv_interface_address_t* addresses,
    int count);
  
  /*
   * File System Methods.
   *
   * The uv_fs_* functions execute a blocking system call asynchronously (in a
   * thread pool) and call the specified callback in the specified loop after
   * completion. If the user gives NULL as the callback the blocking system
   * call will be called synchronously. req should be a pointer to an
   * uninitialized uv_fs_t object.
   *
   * uv_fs_req_cleanup() must be called after completion of the uv_fs_
   * function to free any internal memory allocations associated with the
   * request.
   */
  
  typedef enum {
    UV_FS_UNKNOWN = -1,
    UV_FS_CUSTOM,
    UV_FS_OPEN,
    UV_FS_CLOSE,
    UV_FS_READ,
    UV_FS_WRITE,
    UV_FS_SENDFILE,
    UV_FS_STAT,
    UV_FS_LSTAT,
    UV_FS_FSTAT,
    UV_FS_FTRUNCATE,
    UV_FS_UTIME,
    UV_FS_FUTIME,
    UV_FS_CHMOD,
    UV_FS_FCHMOD,
    UV_FS_FSYNC,
    UV_FS_FDATASYNC,
    UV_FS_UNLINK,
    UV_FS_RMDIR,
    UV_FS_MKDIR,
    UV_FS_RENAME,
    UV_FS_READDIR,
    UV_FS_LINK,
    UV_FS_SYMLINK,
    UV_FS_READLINK,
    UV_FS_CHOWN,
    UV_FS_FCHOWN
  } uv_fs_type;
  
  /* uv_fs_t is a subclass of uv_req_t */
  struct uv_fs_s {
    UV_REQ_FIELDS
    uv_fs_type fs_type;
    uv_loop_t* loop;
    uv_fs_cb cb;
    ssize_t result;
    void* ptr;
    const char* path;
    uv_stat_t statbuf;  /* Stores the result of uv_fs_stat and uv_fs_fstat. */
    UV_FS_PRIVATE_FIELDS
  };
  
  UV_EXTERN void uv_fs_req_cleanup(uv_fs_t* req);
  
  UV_EXTERN int uv_fs_close(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_open(uv_loop_t* loop, uv_fs_t* req, const char* path,
      int flags, int mode, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_read(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      void* buf, size_t length, int64_t offset, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_unlink(uv_loop_t* loop, uv_fs_t* req, const char* path,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_write(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      void* buf, size_t length, int64_t offset, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_mkdir(uv_loop_t* loop, uv_fs_t* req, const char* path,
      int mode, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_rmdir(uv_loop_t* loop, uv_fs_t* req, const char* path,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_readdir(uv_loop_t* loop, uv_fs_t* req,
      const char* path, int flags, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_stat(uv_loop_t* loop, uv_fs_t* req, const char* path,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_fstat(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_rename(uv_loop_t* loop, uv_fs_t* req, const char* path,
      const char* new_path, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_fsync(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_fdatasync(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_ftruncate(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      int64_t offset, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_sendfile(uv_loop_t* loop, uv_fs_t* req, uv_file out_fd,
      uv_file in_fd, int64_t in_offset, size_t length, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_chmod(uv_loop_t* loop, uv_fs_t* req, const char* path,
      int mode, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_utime(uv_loop_t* loop, uv_fs_t* req, const char* path,
      double atime, double mtime, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_futime(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      double atime, double mtime, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_lstat(uv_loop_t* loop, uv_fs_t* req, const char* path,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_link(uv_loop_t* loop, uv_fs_t* req, const char* path,
      const char* new_path, uv_fs_cb cb);
  
  /*
   * This flag can be used with uv_fs_symlink on Windows
   * to specify whether path argument points to a directory.
   */
  #define UV_FS_SYMLINK_DIR          0x0001
  
  /*
   * This flag can be used with uv_fs_symlink on Windows
   * to specify whether the symlink is to be created using junction points.
   */
  #define UV_FS_SYMLINK_JUNCTION     0x0002
  
  UV_EXTERN int uv_fs_symlink(uv_loop_t* loop, uv_fs_t* req, const char* path,
      const char* new_path, int flags, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_readlink(uv_loop_t* loop, uv_fs_t* req, const char* path,
      uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_fchmod(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      int mode, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_chown(uv_loop_t* loop, uv_fs_t* req, const char* path,
      int uid, int gid, uv_fs_cb cb);
  
  UV_EXTERN int uv_fs_fchown(uv_loop_t* loop, uv_fs_t* req, uv_file file,
      int uid, int gid, uv_fs_cb cb);
  
  
  enum uv_fs_event {
    UV_RENAME = 1,
    UV_CHANGE = 2
  };
  
  
  struct uv_fs_event_s {
    UV_HANDLE_FIELDS
    char* filename;
    UV_FS_EVENT_PRIVATE_FIELDS
  };
  
  
  /*
   * uv_fs_stat() based polling file watcher.
   */
  struct uv_fs_poll_s {
    UV_HANDLE_FIELDS
    /* Private, don't touch. */
    void* poll_ctx;
  };
  
  UV_EXTERN int uv_fs_poll_init(uv_loop_t* loop, uv_fs_poll_t* handle);
  
  /*
   * Check the file at `path` for changes every `interval` milliseconds.
   *
   * Your callback is invoked with `status < 0` if `path` does not exist
   * or is inaccessible. The watcher is *not* stopped but your callback is
   * not called again until something changes (e.g. when the file is created
   * or the error reason changes).
   *
   * When `status == 0`, your callback receives pointers to the old and new
   * `uv_stat_t` structs. They are valid for the duration of the callback
   * only!
   *
   * For maximum portability, use multi-second intervals. Sub-second intervals
   * will not detect all changes on many file systems.
   */
  UV_EXTERN int uv_fs_poll_start(uv_fs_poll_t* handle,
                                 uv_fs_poll_cb poll_cb,
                                 const char* path,
                                 unsigned int interval);
  
  UV_EXTERN int uv_fs_poll_stop(uv_fs_poll_t* handle);
  
  
  /*
   * UNIX signal handling on a per-event loop basis. The implementation is not
   * ultra efficient so don't go creating a million event loops with a million
   * signal watchers.
   *
   * Note to Linux users: SIGRT0 and SIGRT1 (signals 32 and 33) are used by the
   * NPTL pthreads library to manage threads. Installing watchers for those
   * signals will lead to unpredictable behavior and is strongly discouraged.
   * Future versions of libuv may simply reject them.
   *
   * Some signal support is available on Windows:
   *
   *   SIGINT is normally delivered when the user presses CTRL+C. However, like
   *   on Unix, it is not generated when terminal raw mode is enabled.
   *
   *   SIGBREAK is delivered when the user pressed CTRL+BREAK.
   *
   *   SIGHUP is generated when the user closes the console window. On SIGHUP the
   *   program is given approximately 10 seconds to perform cleanup. After that
   *   Windows will unconditionally terminate it.
   *
   *   SIGWINCH is raised whenever libuv detects that the console has been
   *   resized. SIGWINCH is emulated by libuv when the program uses an uv_tty_t
   *   handle to write to the console. SIGWINCH may not always be delivered in a
   *   timely manner; libuv will only detect size changes when the cursor is
   *   being moved. When a readable uv_tty_handle is used in raw mode, resizing
   *   the console buffer will also trigger a SIGWINCH signal.
   *
   * Watchers for other signals can be successfully created, but these signals
   * are never generated. These signals are: SIGILL, SIGABRT, SIGFPE, SIGSEGV,
   * SIGTERM and SIGKILL.
   *
   * Note that calls to raise() or abort() to programmatically raise a signal are
   * not detected by libuv; these will not trigger a signal watcher.
   */
  struct uv_signal_s {
    UV_HANDLE_FIELDS
    uv_signal_cb signal_cb;
    int signum;
    UV_SIGNAL_PRIVATE_FIELDS
  };
  
  UV_EXTERN int uv_signal_init(uv_loop_t* loop, uv_signal_t* handle);
  
  UV_EXTERN int uv_signal_start(uv_signal_t* handle,
                                uv_signal_cb signal_cb,
                                int signum);
  
  UV_EXTERN int uv_signal_stop(uv_signal_t* handle);
  
  
  /*
   * Gets load average.
   * See: http://en.wikipedia.org/wiki/Load_(computing)
   * Returns [0,0,0] on Windows.
   */
  UV_EXTERN void uv_loadavg(double avg[3]);
  
  
  /*
   * Flags to be passed to uv_fs_event_init.
   */
  enum uv_fs_event_flags {
    /*
     * By default, if the fs event watcher is given a directory name, we will
     * watch for all events in that directory. This flags overrides this behavior
     * and makes fs_event report only changes to the directory entry itself. This
     * flag does not affect individual files watched.
     * This flag is currently not implemented yet on any backend.
     */
   UV_FS_EVENT_WATCH_ENTRY = 1,
  
    /*
     * By default uv_fs_event will try to use a kernel interface such as inotify
     * or kqueue to detect events. This may not work on remote filesystems such
     * as NFS mounts. This flag makes fs_event fall back to calling stat() on a
     * regular interval.
     * This flag is currently not implemented yet on any backend.
     */
    UV_FS_EVENT_STAT = 2,
  
    /*
     * By default, event watcher, when watching directory, is not registering
     * (is ignoring) changes in it's subdirectories.
     * This flag will override this behaviour on platforms that support it.
     */
    UV_FS_EVENT_RECURSIVE = 3
  };
  
  
  UV_EXTERN int uv_fs_event_init(uv_loop_t* loop, uv_fs_event_t* handle,
      const char* filename, uv_fs_event_cb cb, int flags);
  
  /* Utility */
  
  /* Convert string ip addresses to binary structures */
  UV_EXTERN struct sockaddr_in uv_ip4_addr(const char* ip, int port);
  UV_EXTERN struct sockaddr_in6 uv_ip6_addr(const char* ip, int port);
  
  /* Convert binary addresses to strings */
  UV_EXTERN int uv_ip4_name(struct sockaddr_in* src, char* dst, size_t size);
  UV_EXTERN int uv_ip6_name(struct sockaddr_in6* src, char* dst, size_t size);
  
  /* Cross-platform IPv6-capable implementation of the 'standard' inet_ntop */
  /* and inet_pton functions. On success they return 0. If an error */
  /* the target of the `dst` pointer is unmodified. */
  UV_EXTERN int uv_inet_ntop(int af, const void* src, char* dst, size_t size);
  UV_EXTERN int uv_inet_pton(int af, const char* src, void* dst);
  
  /* Gets the executable path */
  UV_EXTERN int uv_exepath(char* buffer, size_t* size);
  
  /* Gets the current working directory */
  UV_EXTERN int uv_cwd(char* buffer, size_t size);
  
  /* Changes the current working directory */
  UV_EXTERN int uv_chdir(const char* dir);
  
  /* Gets memory info in bytes */
  UV_EXTERN uint64_t uv_get_free_memory(void);
  UV_EXTERN uint64_t uv_get_total_memory(void);
  
  /*
   * Returns the current high-resolution real time. This is expressed in
   * nanoseconds. It is relative to an arbitrary time in the past. It is not
   * related to the time of day and therefore not subject to clock drift. The
   * primary use is for measuring performance between intervals.
   *
   * Note not every platform can support nanosecond resolution; however, this
   * value will always be in nanoseconds.
   */
  UV_EXTERN extern uint64_t uv_hrtime(void);
  
  
  /*
   * Disables inheritance for file descriptors / handles that this process
   * inherited from its parent. The effect is that child processes spawned by
   * this process don't accidentally inherit these handles.
   *
   * It is recommended to call this function as early in your program as possible,
   * before the inherited file descriptors can be closed or duplicated.
   *
   * Note that this function works on a best-effort basis: there is no guarantee
   * that libuv can discover all file descriptors that were inherited. In general
   * it does a better job on Windows than it does on unix.
   */
  UV_EXTERN void uv_disable_stdio_inheritance(void);
  
  /*
   * Opens a shared library. The filename is in utf-8. Returns 0 on success and
   * -1 on error. Call `uv_dlerror(uv_lib_t*)` to get the error message.
   */
  UV_EXTERN int uv_dlopen(const char* filename, uv_lib_t* lib);
  
  /*
   * Close the shared library.
   */
  UV_EXTERN void uv_dlclose(uv_lib_t* lib);
  
  /*
   * Retrieves a data pointer from a dynamic library. It is legal for a symbol to
   * map to NULL. Returns 0 on success and -1 if the symbol was not found.
   */
  UV_EXTERN int uv_dlsym(uv_lib_t* lib, const char* name, void** ptr);
  
  /*
   * Returns the last uv_dlopen() or uv_dlsym() error message.
   */
  UV_EXTERN const char* uv_dlerror(uv_lib_t* lib);
  
  /*
   * The mutex functions return 0 on success or an error code < 0
   * (unless the return type is void, of course).
   */
  UV_EXTERN int uv_mutex_init(uv_mutex_t* handle);
  UV_EXTERN void uv_mutex_destroy(uv_mutex_t* handle);
  UV_EXTERN void uv_mutex_lock(uv_mutex_t* handle);
  UV_EXTERN int uv_mutex_trylock(uv_mutex_t* handle);
  UV_EXTERN void uv_mutex_unlock(uv_mutex_t* handle);
  
  /*
   * Same goes for the read/write lock functions.
   */
  UV_EXTERN int uv_rwlock_init(uv_rwlock_t* rwlock);
  UV_EXTERN void uv_rwlock_destroy(uv_rwlock_t* rwlock);
  UV_EXTERN void uv_rwlock_rdlock(uv_rwlock_t* rwlock);
  UV_EXTERN int uv_rwlock_tryrdlock(uv_rwlock_t* rwlock);
  UV_EXTERN void uv_rwlock_rdunlock(uv_rwlock_t* rwlock);
  UV_EXTERN void uv_rwlock_wrlock(uv_rwlock_t* rwlock);
  UV_EXTERN int uv_rwlock_trywrlock(uv_rwlock_t* rwlock);
  UV_EXTERN void uv_rwlock_wrunlock(uv_rwlock_t* rwlock);
  
  /*
   * Same goes for the semaphore functions.
   */
  UV_EXTERN int uv_sem_init(uv_sem_t* sem, unsigned int value);
  UV_EXTERN void uv_sem_destroy(uv_sem_t* sem);
  UV_EXTERN void uv_sem_post(uv_sem_t* sem);
  UV_EXTERN void uv_sem_wait(uv_sem_t* sem);
  UV_EXTERN int uv_sem_trywait(uv_sem_t* sem);
  
  /*
   * Same goes for the condition variable functions.
   */
  UV_EXTERN int uv_cond_init(uv_cond_t* cond);
  UV_EXTERN void uv_cond_destroy(uv_cond_t* cond);
  UV_EXTERN void uv_cond_signal(uv_cond_t* cond);
  UV_EXTERN void uv_cond_broadcast(uv_cond_t* cond);
  /* Waits on a condition variable without a timeout.
   *
   * Note:
   * 1. callers should be prepared to deal with spurious wakeups.
   */
  UV_EXTERN void uv_cond_wait(uv_cond_t* cond, uv_mutex_t* mutex);
  /* Waits on a condition variable with a timeout in nano seconds.
   * Returns 0 for success or UV_ETIMEDOUT on timeout, It aborts when other
   * errors happen.
   *
   * Note:
   * 1. callers should be prepared to deal with spurious wakeups.
   * 2. the granularity of timeout on Windows is never less than one millisecond.
   * 3. uv_cond_timedwait takes a relative timeout, not an absolute time.
   */
  UV_EXTERN int uv_cond_timedwait(uv_cond_t* cond, uv_mutex_t* mutex,
      uint64_t timeout);
  
  UV_EXTERN int uv_barrier_init(uv_barrier_t* barrier, unsigned int count);
  UV_EXTERN void uv_barrier_destroy(uv_barrier_t* barrier);
  UV_EXTERN void uv_barrier_wait(uv_barrier_t* barrier);
  
  /* Runs a function once and only once. Concurrent calls to uv_once() with the
   * same guard will block all callers except one (it's unspecified which one).
   * The guard should be initialized statically with the UV_ONCE_INIT macro.
   */
  UV_EXTERN void uv_once(uv_once_t* guard, void (*callback)(void));
  
  UV_EXTERN int uv_thread_create(uv_thread_t *tid,
      void (*entry)(void *arg), void *arg);
  UV_EXTERN unsigned long uv_thread_self(void);
  UV_EXTERN int uv_thread_join(uv_thread_t *tid);
  
  /* The presence of these unions force similar struct layout. */
  #define XX(_, name) uv_ ## name ## _t name;
  union uv_any_handle {
    UV_HANDLE_TYPE_MAP(XX)
  };
  
  union uv_any_req {
    UV_REQ_TYPE_MAP(XX)
  };
  #undef XX
  
  
  struct uv_loop_s {
    /* User data - use this for whatever. */
    void* data;
    /* Loop reference counting */
    unsigned int active_handles;
    void* handle_queue[2];
    void* active_reqs[2];
    /* Internal flag to signal loop stop */
    unsigned int stop_flag;
    UV_LOOP_PRIVATE_FIELDS
  };
  
  
  /* Don't export the private CPP symbols. */
  #undef UV_HANDLE_TYPE_PRIVATE
  #undef UV_REQ_TYPE_PRIVATE
  #undef UV_REQ_PRIVATE_FIELDS
  #undef UV_STREAM_PRIVATE_FIELDS
  #undef UV_TCP_PRIVATE_FIELDS
  #undef UV_PREPARE_PRIVATE_FIELDS
  #undef UV_CHECK_PRIVATE_FIELDS
  #undef UV_IDLE_PRIVATE_FIELDS
  #undef UV_ASYNC_PRIVATE_FIELDS
  #undef UV_TIMER_PRIVATE_FIELDS
  #undef UV_GETADDRINFO_PRIVATE_FIELDS
  #undef UV_FS_REQ_PRIVATE_FIELDS
  #undef UV_WORK_PRIVATE_FIELDS
  #undef UV_FS_EVENT_PRIVATE_FIELDS
  #undef UV_SIGNAL_PRIVATE_FIELDS
  #undef UV_LOOP_PRIVATE_FIELDS
  #undef UV_LOOP_PRIVATE_PLATFORM_FIELDS
  
  #ifdef __cplusplus
  }
  #endif
  #endif /* UV_H */
  