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 uv_loop_new 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. Export everything from c-ares as well. */
  #   define UV_EXTERN __declspec(dllexport)
  #   define CARES_BUILDING_LIBRARY 1
  # elif defined(USING_UV_SHARED)
      /* Using shared library. Use shared c-ares as well. */
  #   define UV_EXTERN __declspec(dllimport)
  # else
      /* Building static library. Build c-ares statically as well. */
  #   define UV_EXTERN /* nothing */
  #   define CARES_STATICLIB 1
  # endif
  #elif __GNUC__ >= 4
  # define UV_EXTERN __attribute__((visibility("default")))
  #else
  # define UV_EXTERN /* nothing */
  #endif
  
  
  #define UV_VERSION_MAJOR 0
  #define UV_VERSION_MINOR 8
  
  
  #include <stdint.h> /* int64_t */
  #include <sys/types.h> /* size_t */
  
  #include "ares.h"
  
  #if defined(__unix__) || defined(__POSIX__) || defined(__APPLE__)
  # include "uv-private/uv-unix.h"
  #else
  # include "uv-private/uv-win.h"
  #endif
  
  /* Expand this list if necessary. */
  #define UV_ERRNO_MAP(XX) \
    XX( -1, UNKNOWN, "unknown error") \
    XX(  0, OK, "success") \
    XX(  1, EOF, "end of file") \
    XX(  2, EADDRINFO, "getaddrinfo error") \
    XX(  3, EACCES, "permission denied") \
    XX(  4, EAGAIN, "no more processes") \
    XX(  5, EADDRINUSE, "address already in use") \
    XX(  6, EADDRNOTAVAIL, "") \
    XX(  7, EAFNOSUPPORT, "") \
    XX(  8, EALREADY, "") \
    XX(  9, EBADF, "bad file descriptor") \
    XX( 10, EBUSY, "resource busy or locked") \
    XX( 11, ECONNABORTED, "software caused connection abort") \
    XX( 12, ECONNREFUSED, "connection refused") \
    XX( 13, ECONNRESET, "connection reset by peer") \
    XX( 14, EDESTADDRREQ, "destination address required") \
    XX( 15, EFAULT, "bad address in system call argument") \
    XX( 16, EHOSTUNREACH, "host is unreachable") \
    XX( 17, EINTR, "interrupted system call") \
    XX( 18, EINVAL, "invalid argument") \
    XX( 19, EISCONN, "socket is already connected") \
    XX( 20, EMFILE, "too many open files") \
    XX( 21, EMSGSIZE, "message too long") \
    XX( 22, ENETDOWN, "network is down") \
    XX( 23, ENETUNREACH, "network is unreachable") \
    XX( 24, ENFILE, "file table overflow") \
    XX( 25, ENOBUFS, "no buffer space available") \
    XX( 26, ENOMEM, "not enough memory") \
    XX( 27, ENOTDIR, "not a directory") \
    XX( 28, EISDIR, "illegal operation on a directory") \
    XX( 29, ENONET, "machine is not on the network") \
    XX( 31, ENOTCONN, "socket is not connected") \
    XX( 32, ENOTSOCK, "socket operation on non-socket") \
    XX( 33, ENOTSUP, "operation not supported on socket") \
    XX( 34, ENOENT, "no such file or directory") \
    XX( 35, ENOSYS, "function not implemented") \
    XX( 36, EPIPE, "broken pipe") \
    XX( 37, EPROTO, "protocol error") \
    XX( 38, EPROTONOSUPPORT, "protocol not supported") \
    XX( 39, EPROTOTYPE, "protocol wrong type for socket") \
    XX( 40, ETIMEDOUT, "connection timed out") \
    XX( 41, ECHARSET, "") \
    XX( 42, EAIFAMNOSUPPORT, "") \
    XX( 44, EAISERVICE, "") \
    XX( 45, EAISOCKTYPE, "") \
    XX( 46, ESHUTDOWN, "") \
    XX( 47, EEXIST, "file already exists") \
    XX( 48, ESRCH, "no such process") \
    XX( 49, ENAMETOOLONG, "name too long") \
    XX( 50, EPERM, "operation not permitted") \
    XX( 51, ELOOP, "too many symbolic links encountered") \
    XX( 52, EXDEV, "cross-device link not permitted") \
    XX( 53, ENOTEMPTY, "directory not empty") \
    XX( 54, ENOSPC, "no space left on device") \
    XX( 55, EIO, "i/o error") \
    XX( 56, EROFS, "read-only file system" ) \
    XX( 57, ENODEV, "no such device" )
  
  
  #define UV_ERRNO_GEN(val, name, s) UV_##name = val,
  typedef enum {
    UV_ERRNO_MAP(UV_ERRNO_GEN)
    UV_MAX_ERRORS
  } uv_err_code;
  #undef UV_ERRNO_GEN
  
  #define UV_HANDLE_TYPE_MAP(XX)  \
    XX(ASYNC, async)              \
    XX(CHECK, check)              \
    XX(FS_EVENT, fs_event)        \
    XX(FS_POLL, fs_poll)          \
    XX(IDLE, idle)                \
    XX(NAMED_PIPE, pipe)          \
    XX(POLL, poll)                \
    XX(PREPARE, prepare)          \
    XX(PROCESS, process)          \
    XX(TCP, tcp)                  \
    XX(TIMER, timer)              \
    XX(TTY, tty)                  \
    XX(UDP, udp)                  \
  
  #define UV_REQ_TYPE_MAP(XX)     \
    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 {
    UV_UNKNOWN_HANDLE = 0,
  #define XX(uc, lc) UV_##uc,
    UV_HANDLE_TYPE_MAP(XX)
  #undef XX
    UV_ARES_TASK,
    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;
  
  
  
  typedef struct uv_loop_s uv_loop_t;
  typedef struct uv_ares_task_s uv_ares_task_t;
  typedef struct uv_err_s uv_err_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_getaddrinfo_s uv_getaddrinfo_t;
  typedef struct uv_process_s uv_process_t;
  typedef struct uv_counters_s uv_counters_t;
  typedef struct uv_cpu_info_s uv_cpu_info_t;
  typedef struct uv_interface_address_s uv_interface_address_t;
  /* Request types */
  typedef struct uv_req_s uv_req_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;
  /* uv_fs_event_t is a subclass of uv_handle_t. */
  typedef struct uv_fs_event_s uv_fs_event_t;
  typedef struct uv_fs_poll_s uv_fs_poll_t;
  typedef struct uv_work_s uv_work_t;
  
  
  /*
   * 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 starts the event loop. It blocks until the reference count
   * of the loop drops to zero. Always returns zero.
   */
  UV_EXTERN int uv_run(uv_loop_t*);
  
  /*
   * 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 call
   * uv_run_once() again sometime in the future).
   */
  UV_EXTERN int uv_run_once(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 void uv_update_time(uv_loop_t*);
  UV_EXTERN int64_t uv_now(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 -1 on error.
   *
   * Error details can be obtained by calling uv_last_error(). UV_EOF indicates
   * that the stream has been closed.
   *
   * 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.
   */
  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_getaddrinfo_cb)(uv_getaddrinfo_t* handle, int status,
      struct addrinfo* res);
  typedef void (*uv_exit_cb)(uv_process_t*, int exit_status, int term_signal);
  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);
  typedef void (*uv_walk_cb)(uv_handle_t* handle, void* arg);
  
  /*
  * 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_statbuf_t* prev,
                                const uv_statbuf_t* curr);
  
  typedef enum {
    UV_LEAVE_GROUP = 0,
    UV_JOIN_GROUP
  } uv_membership;
  
  
  struct uv_err_s {
    /* read-only */
    uv_err_code code;
    /* private */
    int sys_errno_;
  };
  
  
  /*
   * Most functions return boolean: 0 for success and -1 for failure.
   * On error the user should then call uv_last_error() to determine
   * the error code.
   */
  UV_EXTERN uv_err_t uv_last_error(uv_loop_t*);
  UV_EXTERN const char* uv_strerror(uv_err_t err);
  UV_EXTERN const char* uv_err_name(uv_err_t err);
  
  
  #define UV_REQ_FIELDS \
    /* public */ \
    void* data; \
    /* private */ \
    ngx_queue_t active_queue; \
    UV_REQ_PRIVATE_FIELDS \
    /* read-only */ \
    uv_req_type type; \
  
  /* 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                                                      \
    /* read-only */                                                             \
    uv_loop_t* loop;                                                            \
    /* public */                                                                \
    uv_close_cb close_cb;                                                       \
    void* data;                                                                 \
    /* read-only */                                                             \
    uv_handle_type type;                                                        \
    /* private */                                                               \
    ngx_queue_t handle_queue;                                                   \
    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.
   */
  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
   * 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 -1 and the error is
   * set to UV_EOF. When nread == -1 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 }
   *   };
   *
   *   // writes "1234"
   *   uv_write(req, stream, a, 2);
   *   uv_write(req, 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);
  
  
  /*
   * 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);
  
  /* Enable/disable Nagle's algorithm. */
  UV_EXTERN int uv_tcp_nodelay(uv_tcp_t* handle, int enable);
  
  /* Enable/disable TCP keep-alive.
   *
   * `ms` 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);
  
  /*
   * This setting applies to Windows only.
   * 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).
   */
  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.
   *          -1 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);
  
  /*
   * 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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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, -1 on error.
   */
  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
    UV_PIPE_PRIVATE_FIELDS
    int ipc; /* non-zero if this pipe is used for passing handles */
  };
  
  /*
   * 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 void 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 may be set to -1 and the error
   * code can be retrieved with uv_last_error. 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.
   *
   * libev wrapper. 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.
   *
   * libev wrapper. 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.
   *
   * libev wrapper. 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.
   *
   * libev wrapper. 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.
   *
   * Wraps libev's ev_timer watcher. 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* timer);
  
  UV_EXTERN int uv_timer_start(uv_timer_t* timer, uv_timer_cb cb,
      int64_t timeout, int64_t repeat);
  
  UV_EXTERN int uv_timer_stop(uv_timer_t* timer);
  
  /*
   * 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 -1 and
   * sets the error to UV_EINVAL.
   */
  UV_EXTERN int uv_timer_again(uv_timer_t* timer);
  
  /*
   * Set the repeat value. 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* timer, int64_t repeat);
  
  UV_EXTERN int64_t uv_timer_get_repeat(uv_timer_t* timer);
  
  
  /* c-ares integration initialize and terminate */
  UV_EXTERN  int uv_ares_init_options(uv_loop_t*,
      ares_channel *channelptr, struct ares_options *options, int optmask);
  
  /* TODO remove the loop argument from this function? */
  UV_EXTERN void uv_ares_destroy(uv_loop_t*, ares_channel channel);
  
  
  /*
   * 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).
   *
   * Return code 0 means that request is accepted and callback will be called
   * with result. Other return codes mean that there will not be a callback.
   * Input arguments may be released after return from this call.
   *
   * uv_freeaddrinfo() must be called after completion to free the addrinfo
   * structure.
   *
   * On error NXDOMAIN the status code will be non-zero and UV_ENOENT returned.
   */
  UV_EXTERN int uv_getaddrinfo(uv_loop_t*, uv_getaddrinfo_t* handle,
      uv_getaddrinfo_cb getaddrinfo_cb, const char* node, const char* service,
      const struct addrinfo* hints);
  
  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;
    /*
     * 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;
  
    /*
     * 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;
  } 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)
  };
  
  /*
   * 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 uv_err_t 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);
  
  
  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;
  };
  
  UV_EXTERN char** uv_setup_args(int argc, char** argv);
  UV_EXTERN uv_err_t uv_get_process_title(char* buffer, size_t size);
  UV_EXTERN uv_err_t uv_set_process_title(const char* title);
  UV_EXTERN uv_err_t uv_resident_set_memory(size_t* rss);
  UV_EXTERN uv_err_t uv_uptime(double* uptime);
  
  /*
   * This allocates cpu_infos array, and sets count.  The array
   * is freed using uv_free_cpu_info().
   */
  UV_EXTERN uv_err_t 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 uv_err_t 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_err_code errorno;
    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. */
    int busy_polling; /* TODO(bnoordhuis) Fold into flags field. */
    unsigned int interval;
    uint64_t start_time;
    char* path;
    uv_fs_poll_cb poll_cb;
    uv_timer_t timer_handle;
    uv_fs_t* fs_req;
    uv_statbuf_t statbuf;
  };
  
  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 i invoked with `status == -1` 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_statbuf_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);
  
  /*
   * Gets load avg
   * See: http://en.wikipedia.org/wiki/Load_(computing)
   * (Returns [0,0,0] for windows and cygwin)
   */
  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
  };
  
  
  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);
  
  /* Gets the executable path */
  UV_EXTERN int uv_exepath(char* buffer, size_t* size);
  
  /* Gets the current working directory */
  UV_EXTERN uv_err_t uv_cwd(char* buffer, size_t size);
  
  /* Changes the current working directory */
  UV_EXTERN uv_err_t 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 proces don't accidently 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.
   *
   * TODO(bb): insert snarky remark to annoy bnoordhuis and the folks at joyent.
   */
  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 libary.
   */
  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, -1 on error
   * (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);
  
  /* 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 int uv_thread_join(uv_thread_t *tid);
  
  /* the presence of these unions force similar struct layout */
  union uv_any_handle {
    uv_tcp_t tcp;
    uv_pipe_t pipe;
    uv_prepare_t prepare;
    uv_check_t check;
    uv_idle_t idle;
    uv_async_t async;
    uv_timer_t timer;
    uv_getaddrinfo_t getaddrinfo;
    uv_fs_event_t fs_event;
  };
  
  union uv_any_req {
    uv_req_t req;
    uv_write_t write;
    uv_connect_t connect;
    uv_shutdown_t shutdown;
    uv_fs_t fs_req;
    uv_work_t work_req;
  };
  
  
  struct uv_counters_s {
    uint64_t async_init;
    uint64_t check_init;
    uint64_t eio_init;
    uint64_t fs_event_init;
    uint64_t fs_poll_init;
    uint64_t handle_init;
    uint64_t idle_init;
    uint64_t pipe_init;
    uint64_t poll_init;
    uint64_t prepare_init;
    uint64_t process_init;
    uint64_t req_init;
    uint64_t stream_init;
    uint64_t tcp_init;
    uint64_t timer_init;
    uint64_t tty_init;
    uint64_t udp_init;
  };
  
  
  struct uv_loop_s {
    UV_LOOP_PRIVATE_FIELDS
    ares_channel channel;
    /* While the channel is active this timer is called once per second to be */
    /* sure that we're always calling ares_process. See the warning above the */
    /* definition of ares_timeout(). */
    uv_timer_t ares_timer; \
    /* RB_HEAD(uv__ares_tasks, uv_ares_task_t) */
    struct uv__ares_tasks { uv_ares_task_t* rbh_root; } ares_handles;
    /* Diagnostic counters */
    uv_counters_t counters;
    /* The last error */
    uv_err_t last_err;
    /* Loop reference counting */
    unsigned int active_handles;
    ngx_queue_t handle_queue;
    ngx_queue_t active_reqs;
    /* User data - use this for whatever. */
    void* data;
  };
  
  
  /* 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_LOOP_PRIVATE_FIELDS
  #undef UV_LOOP_PRIVATE_PLATFORM_FIELDS
  
  #ifdef __cplusplus
  }
  #endif
  #endif /* UV_H */
  