# onBufferEmpty
當緩存區低于最低水位線時觸發此事件。
~~~
function onBufferEmpty(Swoole\Server $serv, int $fd);
~~~
* 設置`server->buffer_low_watermark`來控制緩存區低水位線
* 觸發此事件后，表明當前的`$fd`發送隊列中的數據已被發出，可以繼續向此連接發送數據了
- 序言
- 入門指引
- 環境依賴
- 編譯安裝
- 編譯參數
- 常見錯誤
- Cygwin
- Linux二進制包
- 快速起步
- 創建TCP服務器
- 創建UDP服務器
- 創建Web服務器
- 創建WebSocket服務器
- 設置定時器
- 執行異步任務
- 創建同步TCP客戶端
- 創建異步TCP客戶端
- 網絡通信協議設計
- 使用異步客戶端
- 多進程共享數據
- 使用協程客戶端
- 協程：并發 shell_exec
- 協程：Go + Chan + Defer
- 協程：實現 Go 語言風格的 defer
- 協程：實現 sync.WaitGroup 功能
- 編程須知
- sleep/usleep的影響
- exit/die函數的影響
- while循環的影響
- stat緩存清理
- mt_rand隨機數
- 進程隔離
- 版本更新記錄
- 4.3.1
- 4.3.0 [大版本]
- 4.2.13
- 4.2.12
- 4.2.11
- 4.2.10
- 4.2.9
- 4.2.8
- 4.2.7
- 4.2.0
- 4.1.0
- 4.0.1
- 4.0.0
- 向下不兼容改動
- 新特性使用
- 4.3.0 在 Process 中使用協程
- 4.3.0 延時事件機制改進
- 2.1.2 進程池模塊的使用
- 1.9.24 調度支持 Stream 模式
- 1.9.24 異步客戶端自動解析域名
- 1.9.17 支持異步安全重啟特性
- 1.9.14 使用異步客戶端超時機制
- 1.8.0 使用內置Http異步客戶端
- 1.7.16 使用迭代器遍歷Server所有連接
- 1.7.5 在Server中使用swoole_table
- 1.7.5 swoole_client支持sendfile接口
- 1.7.4 SSL隧道加密TCP-Server
- 1.7.4 task進程中使用毫秒定時器
- 1.7.3 固定包頭+包體協議自動分包
- 1.7.3 onTask直接return取代finish函數
- 1.7.2 swoole_process多進程模塊的使用
- 1.7.2 task進程使用消息隊列
- 項目路線圖
- php.ini選項
- 內核參數調整
- 開發者列表
- 衍生開源項目
- 框架
- 工具
- 分布式
- 通信協議
- 用戶與案例
- 物聯網項目
- 網絡游戲
- 騰訊（Tencent）
- 百度（Baidu.com）
- 閱文集團
- BiliBili（嗶哩嗶哩）
- 車輪互聯（chelun.com）
- (撈月狗) 游戲社區
- 儒博(roobo.com)
- 提交錯誤報告
- 常見問題
- 升級swoole版本的常見問題
- 生成可分發的二進制swoole版本
- 在phpinfo中有在php -m中沒有
- Connection refused是怎么回事
- Resource temporarily unavailable [11]
- Cannot assign requested address [99]
- swoole與node.js相比有哪些優勢
- swoole與golang相比有哪些優勢
- pcre.h: No such file or directory
- undefined symbol: __sync_bool_compare_and_swap_4
- 學習Swoole需要掌握哪些基礎知識
- 同步阻塞與異步非阻塞適用場景
- PHP7環境下出現zend_mm_heap corrupted
- Swoole 項目起源和名字由來
- '__builtin_saddl_overflow' was not declared in this scope
- Server
- 函數列表
- Server::__construct
- Server->set
- Server->on
- Server->addListener
- Server->addProcess
- Server->listen
- Server->start
- Server->reload
- Server->stop
- Server->shutdown
- Server->tick
- Server->after
- Server->defer
- Server->clearTimer
- Server->close
- Server->send
- Server->sendfile
- Server->sendto
- Server->sendwait
- Server->sendMessage
- Server->exist
- Server->pause
- Server->resume
- Server->getClientInfo
- Server->getClientList
- Server->bind
- Server->stats
- Server->task
- Server->taskwait
- Server->taskWaitMulti
- Server->taskCo
- Server->finish
- Server->heartbeat
- Server->getLastError
- Server->getSocket
- Server->protect
- Server->confirm
- 屬性列表
- Server::$setting
- Server::$master_pid
- Server::$manager_pid
- Server::$worker_id
- Server::$worker_pid
- Server::$taskworker
- Server::$connections
- Server::$ports
- 配置選項
- reactor_num
- worker_num
- max_request
- max_conn (max_connection)
- task_worker_num
- task_ipc_mode
- task_max_request
- task_tmpdir
- dispatch_mode
- dispatch_func
- message_queue_key
- daemonize
- backlog
- log_file
- log_level
- heartbeat_check_interval
- heartbeat_idle_time
- open_eof_check
- open_eof_split
- package_eof
- open_length_check
- package_length_type
- package_length_func
- package_max_length
- open_cpu_affinity
- cpu_affinity_ignore
- open_tcp_nodelay
- tcp_defer_accept
- ssl_cert_file
- ssl_method
- ssl_ciphers
- user
- group
- chroot
- pid_file
- pipe_buffer_size
- buffer_output_size
- socket_buffer_size
- enable_unsafe_event
- discard_timeout_request
- enable_reuse_port
- enable_delay_receive
- open_http_protocol
- open_http2_protocol
- open_websocket_protocol
- open_mqtt_protocol
- open_websocket_close_frame
- reload_async
- tcp_fastopen
- request_slowlog_file
- enable_coroutine
- max_coroutine
- task_enable_coroutine
- ssl_verify_peer
- 監聽端口
- 可選參數
- 可選回調
- 連接迭代器
- 預定義常量
- 事件回調函數
- onStart
- onShutdown
- onWorkerStart
- onWorkerStop
- onWorkerExit
- onConnect
- onReceive
- onPacket
- onClose
- onBufferFull
- onBufferEmpty
- onTask
- onFinish
- onPipeMessage
- onWorkerError
- onManagerStart
- onManagerStop
- 高級特性
- 改變Worker進程的用戶/組
- 回調函數中的 reactor_id 和 fd
- Length_Check 和 EOF_Check 的使用
- Worker與Reactor通信模式
- TCP-Keepalive死連接檢測
- TCP服務器心跳維持方案
- 多端口監聽的使用
- 捕獲Server運行期致命錯誤
- Server內存管理機制
- Server的兩種運行模式介紹
- Server中對象的4層生命周期
- 在worker進程內監聽一個Server端口
- 在php-fpm/apache中使用task功能
- 常見問題
- 為什么不要send完后立即close
- 如何在回調函數中訪問外部的變量
- 是否可以共用1個redis或mysql連接
- 關于onConnect/onReceive/onClose順序
- 4種PHP回調函數風格
- 不同的Server程序實例間如何通信
- 錯誤信息：ERROR (9006)
- eventLoop has already been created. unable to create swoole_server
- 壓力測試
- 并發10萬TCP連接的測試
- PHP7+Swoole/Nginx/Golang性能對比
- 全球Web框架權威性能測試 Techempower Web Framework Benchmarks
- Coroutine
- Coroutine
- Coroutine::set
- Coroutine::stats
- Coroutine::create
- Coroutine::exist
- Coroutine::getCid
- Coroutine::getPcid
- Coroutine::getContext
- Coroutine::defer
- Coroutine::list
- Coroutine::getBackTrace
- Coroutine::yield
- Coroutine::resume
- Coroutine::fread
- Coroutine::fgets
- Coroutine::fwrite
- Coroutine::sleep
- Coroutine::gethostbyname
- Coroutine::getaddrinfo
- Coroutine::exec
- Coroutine::readFile
- Coroutine::writeFile
- Coroutine::statvfs
- Coroutine\Channel
- Coroutine\Channel->__construct
- Coroutine\Channel->push
- Coroutine\Channel->pop
- Coroutine\Channel->stats
- Coroutine\Channel->close
- Coroutine\Channel->length
- Coroutine\Channel->isEmpty
- Coroutine\Channel->isFull
- Coroutine\Channel->$capacity
- Coroutine\Channel->$errCode
- Coroutine\Client
- Coroutine\Client->connect
- Coroutine\Client->send
- Coroutine\Client->recv
- Coroutine\Client->close
- Coroutine\Client->peek
- Coroutine\Http\Client
- 屬性列表
- Coroutine\Http\Client->get
- Coroutine\Http\Client->post
- Coroutine\Http\Client->upgrade
- Coroutine\Http\Client->push
- Coroutine\Http\Client->recv
- Coroutine\Http\Client->addFile
- Coroutine\Http\Client->addData
- Coroutine\Http\Client->download
- Coroutine\Http2\Client
- Coroutine\Http2\Client->__construct
- Coroutine\Http2\Client->set
- Coroutine\Http2\Client->connect
- Coroutine\Http2\Client->send
- Coroutine\Http2\Client->write
- Coroutine\Http2\Client->recv
- Coroutine\Http2\Client->close
- Coroutine\Redis
- Coroutine\Redis::__construct
- Coroutine\Redis::setOptions
- 屬性列表
- 事務模式
- 訂閱模式
- Coroutine\Socket
- Coroutine\Socket::__construct
- Coroutine\Socket->bind
- Coroutine\Socket->listen
- Coroutine\Socket->accept
- Coroutine\Socket->connect
- Coroutine\Socket->send
- Coroutine\Socket->sendAll
- Coroutine\Socket->recv
- Coroutine\Socket->recvAll
- Coroutine\Socket->sendto
- Coroutine\Socket->recvfrom
- Coroutine\Socket->getsockname
- Coroutine\Socket->getpeername
- Coroutine\Socket->close
- Coroutine\MySQL
- 屬性列表
- Coroutine\MySQL->connect
- Coroutine\MySQL->query
- Coroutine\MySQL->prepare
- Coroutine\MySQL->escape
- Coroutine\MySQL->begin
- Coroutine\MySQL->commit
- Coroutine\MySQL->rollback
- Coroutine\MySQL\Statement->execute
- Coroutine\MySQL\Statement->fetch
- Coroutine\MySQL\Statement->fetchAll
- Coroutine\MySQL\Statement->nextResult
- Coroutine\PostgreSQL
- Coroutine\PostgreSQL->connect
- Coroutine\PostgreSQL->query
- Coroutine\PostgreSQL->fetchAll
- Coroutine\PostgreSQL->affectedRows
- Coroutine\PostgreSQL->numRows
- Coroutine\PostgreSQL->fetchObject
- Coroutine\PostgreSQL->fetchAssoc
- Coroutine\PostgreSQL->fetchArray
- Coroutine\PostgreSQL->fetchRow
- Coroutine\PostgreSQL->metaData
- Coroutine\PostgreSQL->prepare
- Server
- 并發調用
- setDefer 機制
- 子協程+通道
- 實現原理
- 協程與線程
- 發送數據協程調度
- 協程內存開銷
- 4.0 協程實現原理
- 協程客戶端超時規則
- 協程執行流程
- 常見問題
- 運行中出現 Fatal error: Maximum function nesting level of '1000' reached, aborting!
- 為什么只能在回調函數中使用協程客戶端
- 支持協程的回調方法列表
- 錯誤信息： XXXX client has already been bound to another coroutine
- Swoole4 協程與 PHP 的 Yield/Generator 協程有什么區別
- Swoole4 協程與 Go 協程有哪些區別
- 編程須知
- 在多個協程間共用同一個協程客戶端
- 禁止使用協程 API 的場景（2.x 版本）
- 使用類靜態變量/全局變量保存上下文
- 退出協程
- 異常處理
- 擴展組件
- MongoDB
- 編程調試
- Runtime
- 文件操作
- 睡眠函數
- 開關選項
- 嚴格模式
- Timer
- swoole_timer_tick
- swoole_timer_after
- swoole_timer_clear
- Memory
- Lock
- swoole_lock->__construct
- swoole_lock->lock
- swoole_lock->trylock
- swoole_lock->unlock
- swoole_lock->lock_read
- swoole_lock->trylock_read
- swoole_lock->lockwait
- Buffer
- swoole_buffer->__construct
- swoole_buffer->append
- swoole_buffer->substr
- swoole_buffer->clear
- swoole_buffer->expand
- swoole_buffer->write
- swoole_buffer->read
- swoole_buffer->recycle
- Table
- Table->__construct
- Table->column
- Table->create
- Table->set
- Table->incr
- Table->decr
- Table->get
- Table->exist
- Table->count
- Table->del
- Atomic
- swoole_atomic->__construct
- swoole_atomic->add
- swoole_atomic->sub
- swoole_atomic->get
- swoole_atomic->set
- swoole_atomic->cmpset
- swoole_atomic->wait
- swoole_atomic->wakeup
- mmap
- swoole_mmap::open
- Channel
- Channel->__construct
- Channel->push
- Channel->pop
- Channel->stats
- Serialize
- swoole_serialize::pack
- swoole_serialize::unpack
- Http\Server
- Http\Server
- Http\Server->on
- Http\Server->start
- Http\Request
- Http\Request->$header
- Http\Request->$server
- Http\Request->$get
- Http\Request->$post
- Http\Request->$cookie
- Http\Request->$files
- Http\Request->rawContent
- Http\Request->getData
- Http\Response
- Http\Response->header
- Http\Response->cookie
- Http\Response->status
- Http\Response->gzip
- Http\Response->redirect
- Http\Response->write
- Http\Response->sendfile
- Http\Response->end
- Http\Response->detach
- Http\Response::create
- 配置選項
- upload_tmp_dir
- http_parse_post
- document_root
- http_compression
- 常見問題
- CURL發送POST請求服務器端超時
- 使用Chrome訪問服務器會產生2次請求
- GET/POST請求的最大尺寸
- WebSocket\Server
- 回調函數
- onHandShake
- onOpen
- onMessage
- 函數列表
- WebSocket\Server->push
- WebSocket\Server->exist
- WebSocket\Server::pack
- WebSocket\Server::unpack
- WebSocket\Server->disconnect
- WebSocket\Server->isEstablished
- 預定義常量
- 常見問題
- 配置選項
- WebSocket\Frame
- Redis\Server
- 方法
- Redis\Server->setHandler
- Redis\Server::format
- 常量
- Process
- Process::__construct
- Process->start
- Process->name
- Process->exec
- Process->write
- Process->read
- Process->setTimeout
- Process->setBlocking
- Process->useQueue
- Process->statQueue
- Process->freeQueue
- Process->push
- Process->pop
- Process->close
- Process->exit
- Process::kill
- Process::wait
- Process::daemon
- Process::signal
- Process::alarm
- Process::setAffinity
- Process::exportSocket
- Process\Pool
- Process\Pool::__construct
- Process\Pool->on
- Process\Pool->listen
- Process\Pool->write
- Process\Pool->start
- Process\Pool->getProcess
- Client
- 方法列表
- swoole_client::__construct
- swoole_client->set
- swoole_client->on
- swoole_client->connect
- swoole_client->isConnected
- swoole_client->getSocket
- swoole_client->getSockName
- swoole_client->getPeerName
- swoole_client->getPeerCert
- swoole_client->send
- swoole_client->sendto
- swoole_client->sendfile
- swoole_client->recv
- swoole_client->close
- swoole_client->sleep
- swoole_client->wakeup
- swoole_client->enableSSL
- 回調函數
- onConnect
- onError
- onReceive
- onClose
- onBufferFull
- onBufferEmpty
- 屬性列表
- swoole_client->errCode
- swoole_client->sock
- swoole_client->reuse
- 并行
- swoole_client_select
- TCP客戶端異步連接
- SWOOLE_KEEP建立TCP長連接
- 常量
- 配置選項
- ssl_verify_peer
- ssl_host_name
- ssl_cafile
- ssl_capath
- package_length_func
- http_proxy_host
- 常見問題
- Event
- swoole_event_add
- swoole_event_set
- swoole_event_isset
- swoole_event_write
- swoole_event_del
- swoole_event_exit
- swoole_event_defer
- swoole_event_cycle
- swoole_event_wait
- swoole_event_dispatch
- 常見問題
- epoll_wait 偶爾會用很長時間
- 異步回調
- 異步文件系統IO
- swoole_async_readfile
- swoole_async_writefile
- swoole_async_read
- swoole_async_write
- swoole_async_dns_lookup
- swoole_async::exec
- 異步MySQL客戶端
- swoole_mysql->__construct
- swoole_mysql->on
- swoole_mysql->connect
- swoole_mysql->escape
- swoole_mysql->query
- swoole_mysql->begin
- swoole_mysql->commit
- swoole_mysql->rollback
- swoole_mysql->close
- 異步Redis客戶端
- swoole_redis->__construct
- swoole_redis->on
- swoole_redis->connect
- swoole_redis->__call
- swoole_redis->close
- 異步Http/WebSocket客戶端
- swoole_http_client->__construct
- swoole_http_client->set
- swoole_http_client->setMethod
- swoole_http_client->setHeaders
- swoole_http_client->setCookies
- swoole_http_client->setData
- swoole_http_client->addFile
- swoole_http_client->get
- swoole_http_client->post
- swoole_http_client->upgrade
- swoole_http_client->push
- swoole_http_client->execute
- swoole_http_client->download
- swoole_http_client->close
- 異步Http2.0客戶端
- swoole_http2_client->__construct
- swoole_http2_client->get
- swoole_http2_client->post
- swoole_http2_client->setHeaders
- swoole_http2_client->setCookies
- 高級
- Swoole的實現
- Reactor線程
- Manager進程
- Worker進程
- Reactor、Worker、TaskWorker的關系
- Task/Finish特性的用途
- 在php-fpm或apache中使用swoole
- Swoole異步與同步的選擇
- TCP/UDP壓測工具
- swoole服務器如何做到無人值守100%可用
- MySQL的連接池、異步、斷線重連
- PHP中哪些函數是同步阻塞的
- 守護進程程序常用數據結構
- 隊列（Queue）
- 堆（Heap）
- 定長數組（SplFixedArray）
- 使用jemalloc優化swoole內存分配性能
- C開發者如何使用Swoole
- C++開發者如何使用Swoole
- 使用systemd管理swoole服務
- 網卡中斷設置
- 將Swoole靜態編譯內嵌到PHP
- 異步回調程序內存管理
- 日志等級控制
- 使用 asan 內存檢測
- Windows編譯
- Swoole協程之旅-前篇
- Swoole協程之旅-中篇
- Swoole協程之旅-后篇
- 協程CPU密集場景調度實現
- 其他
- 函數列表
- swoole_set_process_name
- swoole_version
- swoole_strerror
- swoole_errno
- swoole_get_local_ip
- swoole_clear_dns_cache
- swoole_get_local_mac
- swoole_cpu_num
- swoole_last_error
- Swoole社區
- Swoole技術會議
- 工作組（Working Groups）
- 參與開源項目指引
- 捐贈Swoole項目
- 加入Swoole開發組
- 非協程特性獨立擴展 （swoole_async）
- 附錄：Linux信號列表
- 附錄：Linux錯誤碼(errno)列表
- 附錄：Swoole錯誤碼列表
- 附錄：TCP連接的狀態
- 附錄：tcpdump抓包工具的使用
- 附錄：strace工具的使用
- 附錄：gdb工具的使用
- 附錄：lsof工具的使用
- 附錄：perf工具的使用
- 附錄：編譯PHP擴展的相關工具
- 備用：已移除的歷史特性
- swoole_server->handler
- task_worker_max
- swoole_server->addtimer
- swoole_server->deltimer
- onTimer
- swoole_timer_add
- swoole_timer_del
- swoole_get_mysqli_sock
- swoole_mysql_query
- onMasterConnect
- onMasterClose
- Nginx/Golang/Swoole/Node.js的性能對比
- Coroutine::call_user_func
- Coroutine::call_user_func_array
- Coroutine\Channel::select
- task_async
- 歷史：版本更新記錄（1.x）
- 1.10.3
- 1.10.2
- 1.10.1
- 1.10.0
- 1.9.23
- 1.9.22
- 1.9.19
- 1.9.18
- 1.9.17
- 1.9.16
- 1.9.15
- 1.9.14
- 1.9.12
- 1.9.11
- 1.9.9
- 1.9.7
- 1.9.6
- 1.9.5
- 1.9.4
- 1.9.3
- 1.9.2
- 1.9.1
- 1.9.0
- 1.8.13
- 1.8.12
- 1.8.11
- 1.8.10
- 1.8.9
- 1.8.8
- 1.8.7
- 1.8.6
- 1.8.5
- 1.8.4
- 1.8.3
- 1.8.2
- 1.8.1
- 1.8.0
- 1.7.22
- 1.7.21
- 1.7.20
- 1.7.19
- 1.7.18
- 1.7.17
- 1.7.16
- 1.7.15
- 1.7.14
- 1.7.13
- 1.7.12
- 1.7.11
- 1.7.10
- 1.7.9
- 1.7.8
- 1.7.7
- 1.7.6
- 1.7.5
- v1.5
- v1.6
- v1.7
- 歷史：版本更新記錄（2.x）
- 2.0.1-Alpha
- 2.0.5
- 2.0.9
- 1.9.21
- 2.0.10
- 2.0.11
- 2.0.12
- 2.0.13
- 2.1.1
- 2.1.2
- 2.2.0
- 3.0.0
- 歷史：版本更新記錄（4.x）
- 4.0.3
- 4.0.2
- 4.0.4
- 4.1.1
- 4.1.2
- 4.2.1
- 4.2.2
- 4.2.3
- 4.2.4
- 4.2.5
- 4.2.6
- 4.2.7
- 4.2.9
- 4.2.8
- 社區文檔版權申明
- 社區文檔編輯條例