【正文】 This flag39。s threadpool for example) that can39。s the right thing, believe me).EVFLAG_NOENV If this flag bit is or39。Example: Restrict libev to the select and poll backends, and do not allow environment settings to be taken into account: ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV)。t know what event loop to use, use the one returned from this function (or via the EV_DEFAULT macro).Note that this function is not threadsafe, so if you want to use it from multiple threads, you have to employ some kind of mutex (note also that this case is unlikely, as loops cannot be shared easily between threads anyway).The default loop is the only loop that can handle ev_child watchers, and to do this, it always registers a handler for SIGCHLD. If this is a problem for your application you can either create a dynamic loop with ev_loop_new which doesn39。 } ... ev_set_syserr_cb (fatal_error)。t go away, do bad stuff (such as abort).Example: This is basically the same thing that libev does internally, too. static void fatal_error (const char *msg) { perror (msg)。 } } ... ev_set_allocator (persistent_realloc)。 if (newptr) return newptr。 ev_supported_backends (), likewise for remended ones.See the description of ev_embed watchers for more info.ev_set_allocator (void *(*cb)(void *ptr, long size)) Sets the allocation function to use (the prototype is similar the semantics are identical to the realloc C89/SuS/POSIX function). It is used to allocate and free memory (no surprises here). If it returns zero when memory needs to be allocated (size != 0), the library might abort or take some potentially destructive action.Since some systems (at least OpenBSD and Darwin) fail to implement correct realloc semantics, libev will use a wrapper around the system realloc and free functions by default.You could override this function in highavailability programs to, say, free some memory if it cannot allocate memory, to use a special allocator, or even to sleep a while and retry until some memory is available.Example: Replace the libev allocator with one that waits a bit and then retries (example requires a standardspliant realloc). static void * persistent_realloc (void *ptr, size_t size) { for (。 EVBACKEND_EPOLL))。 ev_version_minor () = EV_VERSION_MINOR))。t accidentally been linked against the wrong version (note, however, that this will not detect other ABI mismatches, such as LFS or reentrancy). assert ((libev version mismatch, ev_version_major () == EV_VERSION_MAJOR amp。Usually, it39。如果需要，你可以比較全局字段EV_VERSION_MAJOR 和 EV_VERSION_MINOR，它們表明了你的程序編譯完成后的庫版本。ev_now_update和ev_now組合在一起使用更好ev_sleep (ev_tstamp interval) Sleep for the given interval: The current thread will be blocked until either it is interrupted or the given time interval has passed (approximately it might return a bit earlier even if not interrupted). Returns immediately if interval = 0.休眠指定的時間間隔：當前線程將被阻塞直到它被中斷或者給定的時間間隔已經(jīng)過去（近視值即使沒有中斷它也會返回的早一點）。ev_tstamp ev_time () Returns the current time as libev would use it. Please note that the ev_now function is usually faster and also often returns the timestamp you actually want to know. Also interesting is the bination of ev_now_update and ev_now.返回libev使用它時的當前時間。這些在正常情況下不會觸發(fā)，他們表明在libev存在一個bug或者更大的錯誤。 表明這里有l(wèi)ibev調(diào)用端的編程錯誤需要修正。NDEBUGassertabort()。ev_set_syserr_cb設(shè)定的回調(diào)函數(shù),它假設(shè)這個回調(diào)函數(shù)可修正這個問題或者是退出。Unlike the name ponent stamp might indicate, it is also used for time differences (. delays) throughout libev.不同名稱的組件戳可能表明，它在整個libev中也用于不同的時間段（比如延遲）。TIME REPRESENTATION 時間描述Libev represents time as a single floating point number, representing the (fractional) number of seconds since the (POSIX) epoch (in practice somewhere near the beginning of 1970, details are plicated, don39。更多的關(guān)于各種配置選項請查看本手冊中的EMBED章節(jié)部分。CONVENTIONS 約定Libev is very configurable. In this manual the default (and most mon) configuration will be described, which supports multiple event loops. For more info about various configuration options please have a look at EMBED section in this manual. If libev was configured without support for multiple event loops, then all functions taking an initial argument of name loop (which is always of type struct ev_loop *) will not have this argument.LIBEV非常容易配置。FEATURES 特點Libev supports select, poll, the Linuxspecific epoll, the BSDspecific kqueue and the Solarisspecific event port mechanisms for file descriptor events (ev_io), the Linux inotify interface (for ev_stat), Linux eventfd/signalfd (for faster and cleaner interthread wakeup (ev_async)/signal handling (ev_signal)) relative timers (ev_timer), absolute timers with customised rescheduling (ev_periodic), synchronous signals (ev_signal), process status change events (ev_child), and event watchers dealing with the event loop mechanism itself (ev_idle, ev_embed, ev_prepare and ev_check watchers) as well as file watchers (ev_stat) and even limited support for fork events (ev_fork).Libev支持 select,poll,Linux特有的epoll,BSD特有的kqueue以及Solaris特有的文件描述符事件端口機制（ev_io），Linux信息通知接口（ev_stat），Linux事件文件/信號文件（為了更快更完整的喚醒沉睡線程（ev_async）/信號捕捉（ev_signal））相對定時器（ev_timer），用戶自定義的絕對定時器（ev_periodic），同步信號（ev_signal），進程狀態(tài)改變事件（ev_child），和通過事件循環(huán)機制實現(xiàn)的事件觀察者管理本身（ev_idle,ev_embed,ev_prepare和ev_check監(jiān)控）也和文件監(jiān)控（ev_stat）和有限支持的派生子進程事件（ev_fork）一樣。ABOUT LIBEV 關(guān)于libevLibev is an event loop: you register interest in certain events (such as a file descriptor being readable or a timeout occurring), and it will manage these event sources and provide your program with events.Libev是一個事件循環(huán)：你注冊感興趣的特定事件（比如一個文件可以讀取時或者發(fā)生超時時），它將管理這些事件源，將這些事件反饋給你的程序。WHAT TO READ WHEN IN A HURRY 快速閱讀This manual tries to be very detailed, but unfortunately, this also makes it very long. If you just want to know the basics of libev, I suggest reading ANATOMY OF A WATCHER, then the EXAMPLE PROGRAM above and look up the missing function