1 typedef void (*)(struct ev_loop *loop, ev_TYPE *watcher, int revents) callback; // callback都是这种类型 2 ev_init (ev_TYPE *watcher, callback); // 初始化watcher 3 ev_TYPE_set (ev_TYPE *watcher, [args]); // 设置watcher 4 ev_TYPE_init (ev_TYPE *watcher, callback, [args]); // 通常使用这个函数最方便，初始化和设置都在这里 5 ev_TYPE_start (loop, ev_TYPE *watcher); // 注册watcher 6 ev_TYPE_stop (loop, ev_TYPE *watcher); // 注销watcher 7 ev_set_priority (ev_TYPE *watcher, int priority); // 设置优先级 8 ev_feed_event (loop, ev_TYPE *watcher, int revents); // 这个做跨线程通知非常有用，相当于触发了某个事件。 9 bool ev_is_active (ev_TYPE *watcher); // watcher是否active.10 bool ev_is_pending (ev_TYPE *watcher); // watcher是否pending.11 int ev_clear_pending (loop, ev_TYPE *watcher); // 清除watcher pending状态并且返回事件

 1 #include <stdio.h> 2 #include <string.h> 3 #include <unistd.h> 4 #include <ev.h> 5  6  7 static void stdin_callback(struct ev_loop *loop,ev_io *w,int revents) 8 { 9     char str[1024];10     if(revents & EV_READ)11     {12         //stdin might have data for us13         printf("有数据可读\n");14         scanf("%s",str);15         ev_io_stop(loop,w);16     }17     else if(revents & EV_WRITE)18     {19         //stdout might have data for us20         printf("有数据输出\n");21         //ev_break(loop,EVBREAK_ONE);22     }23     printf("water:%d\n",ev_is_active(w));24 }25 26 int main(int argc,char **argv)27 {28     struct ev_loop * main_loop = ev_default_loop(0);29     //这里的ev_default_loop可以使用ev_loop_new动态分配一个，然后使用ev_loop_destroy销毁。30     //struct ev_loop * epoller = ev_loop_new(EVBACKEND_EPOLL | EVFLAG_NOENV);31     //这里一般是使用EVBACKEND_EPOLL模型，同样的还有EVBACKEND_SELECT EVBACKEND_POLL EVBACKEND_KQUEUE EVBACKEND_DEVPOLL EVBACKEND_PORT 如果默认，那么ev会自动判断系统环境，选择最适合的模型，Linux一般为epoll bsd一般为kqueue什么的。32     ev_io stdin_watcher;33     ev_init(&stdin_watcher,stdin_callback);34     ev_io_set(&stdin_watcher,STDIN_FILENO,EV_READ|EV_WRITE);35     ev_io_start(main_loop,&stdin_watcher);36 37     //ev_run(main_loop,EVRUN_ONCE);38 39     //void ev_set_io_collect_interval (EV_P_ ev_tstamp interval);//这个是设置轮询的时间40     //typedef double ev_tstamp41     ev_set_io_collect_interval(main_loop,2.);//2秒42     ev_run(main_loop,0);43     //ev_is_active(ev_TYPE * watcher);//用于判断watcher是否为active44     printf("main:%d\n",ev_is_active(&stdin_watcher));45 46     //initialiased.调用init函数初始化47     //active.调用start进行注册48     //pending.已经触发事件但是没有处理49     //inactive.调用stop注销。这个状态等同于initialised这个状态50 51     return 0;52 }

 1 #include <stdio.h> 2 #include <string.h> 3 #include <unistd.h> 4 #include <ev.h> 5  6 static void three_second_callback(struct ev_loop *loop,ev_timer *w,int revents) 7 { 8     //这是一个3秒触发的计时器 9     printf("3秒触发器\n");10 }11 static void five_second_callback(struct ev_loop *loop,ev_timer *w,int revents)12 {13     //这是一个5秒触发的计时器14     printf("5秒触发器\n");15 }16 static void the_second_callback(struct ev_loop *loop,ev_timer *w,int revents)17 {18     //这是一个10秒触发的计时器19     printf("10秒触发器\n");20 }21 22 int main(int argc, char **args)23 {24     struct ev_loop * main_loop=ev_default_loop(0);25 26     ev_timer mytimer_watcher3;27     ev_timer mytimer_watcher5;28 29     ev_init(&mytimer_watcher3,three_second_callback);30     ev_timer_set(&mytimer_watcher3,3,0);31     ev_timer_start(main_loop,&mytimer_watcher3);32     ev_run(main_loop,0);//这个在ev_io上是一直判断的。但是这个触发器只会触发一次，不会每3秒触发一次。这是个问题。33 34     ev_init(&mytimer_watcher5,five_second_callback);35     ev_timer_set(&mytimer_watcher5,5,0);36     ev_timer_start(main_loop,&mytimer_watcher5);37     ev_run(main_loop,0);38 39 40     ev_timer_start(main_loop,&mytimer_watcher3);41     ev_timer_start(main_loop,&mytimer_watcher5);42     ev_run(main_loop,0);//这里不会等待3，5秒，而是上一步后，直接输出,可见触发器只能用一次43 44     ev_timer_set(&mytimer_watcher3,3,0);45     ev_timer_start(main_loop,&mytimer_watcher3);46     ev_timer_set(&mytimer_watcher5,5,0);47     ev_timer_start(main_loop,&mytimer_watcher5);48     ev_run(main_loop,0);//这里就会等待了，要重新set一遍49 50 51     return 0;52 }

 1 #include <stdio.h> 2 #include <string.h> 3 #include <unistd.h> 4 #include <ev.h> 5  6 static void periodic_callback(struct ev_loop *loop,ev_periodic * w, int revents) 7 { 8     printf("每3秒执行一次\n"); 9     //ev_break(loop,EVBREAK_ALL);10 }11 12 //ev_tstamp=double13 static ev_tstamp periodic_scheduler_callback(ev_periodic *w,ev_tstamp now)14 {15     return now+3;//注意时间要加上个now，是一个绝对时间16 }17 18 int main(int argc, char **args)19 {20     struct ev_loop * main_loop=ev_default_loop(0);21 22     ev_periodic periodic_watcher;23     //下面这个是第3个参数为3 是一个表达式24     ev_init(&periodic_watcher,periodic_callback);25     ev_periodic_set(&periodic_watcher,0,3,0);26     ev_periodic_start(main_loop,&periodic_watcher);27     ev_run(main_loop,0);28 29     //如果时间周期计算方式，不能通过一个表达式来表示，那么可以通过一个函数来表示，放在set的第4个参数30     ev_init(&periodic_watcher,periodic_callback);31     ev_periodic_set(&periodic_watcher,0,0,periodic_scheduler_callback);32     ev_periodic_start(main_loop,&periodic_watcher);33     ev_run(main_loop,0);34     //注意上下两部分不能通过运行，要注释掉一个才可以看到效果35     return 0;36 }

 1 #include <stdio.h> 2 #include <string.h> 3 #include <unistd.h> 4 #include <signal.h> 5 #include <ev.h> 6  7 static void sigint_callback(struct ev_loop * loop,ev_signal *w,int revents) 8 { 9     if(revents & EV_SIGNAL)//用这个可以判断这次进来的是不是ev_signal 如果一个callback回调函数复用的话，就可以用这个来区分10     {11         printf("signal SIGINT\n");12         ev_break(loop, EVBREAK_ALL);13     }14 }15 16 static void sigquit_callback(struct ev_loop * loop,ev_signal *w,int revents)17 {18     printf("signal SIGQUIT\n");19     ev_break(loop, EVBREAK_ALL);20 }21 22 int main(int argc, char **args)23 {24     struct ev_loop * main_loop=ev_default_loop(0);25 26     ev_signal sigint_watcher;27     ev_signal sigquit_watcher;28 29     ev_init(&sigint_watcher,sigint_callback);30     ev_signal_set(&sigint_watcher,SIGINT/*Other want to catch*/);//这里多个信号不能用或符号| 连接起来31     ev_signal_start(main_loop,&sigint_watcher);32 33     ev_init(&sigquit_watcher,sigquit_callback);34     ev_signal_set(&sigquit_watcher,SIGQUIT/*Other want to catch*/);35     ev_signal_start(main_loop,&sigquit_watcher);36 37     ev_run(main_loop,0);38 39     return 0;40 }

 1 #include <stdio.h> 2 #include <string.h> 3 #include <unistd.h> 4 #include <stdlib.h> 5 #include <sys/wait.h> 6 #include <ev.h> 7  8 static void child_callback(struct ev_loop *loop,ev_child *w,int revents) 9 {10     ev_child_stop(loop,w);11     printf("Process %d exited with status %d\n",w->rpid,w->rstatus);12 }13 14 int main(int argc, char **args)15 {16     struct ev_loop * main_loop=ev_default_loop(0);17     pid_t pid;18 19     ev_child child_watcher;20 21     pid=fork();22     if(pid<0)23     {24         printf("Fork Error\n");25         return -1;26     }27     else if(pid==0)//child28     {29         printf("child doing..\n");30         return 0;31     }32     else //father33     {34         sleep(2);//即使让子进程先执行，最后还是可以捕获到。35         ev_init(&child_watcher,child_callback);36         ev_child_set(&child_watcher,pid,0);37         //ev_child_start(EV_DEFAULT_ &child_watcher);38         ev_child_start(main_loop,&child_watcher);39         ev_run(main_loop,0);40     }41 42     //waitpid(pid,0,0);43     return 0;44 }

 1 #include <stdio.h> 2 #include <string.h> 3 #include <unistd.h> 4 #include <stdlib.h> 5 #include <ev.h> 6  7 static void stat_callback(struct ev_loop *loop,ev_stat *w, int revents) 8 { 9     if(w->attr.st_nlink)10     {11         printf("The file size %ld\n",(long)w->attr.st_size);12     }13     else14     {15         printf("文件不存在\n");16     }17 }18 19 int main(int argc, char **args)20 {21     struct ev_loop *main_loop=ev_default_loop(0);22 23     ev_stat stat_watcher;24     ev_init(&stat_watcher,stat_callback);25     ev_stat_set(&stat_watcher,"/home/myuser/hello.txt",0);26     ev_stat_start(main_loop,&stat_watcher);27 28     ev_run(main_loop,0);29     return 0;30 }

文档原文:The previous attributes of the file. The callback gets invoked wheneverC<prev> != C<attr>, or, more precisely, one or more of these membersdiffer: C<st_dev>, C<st_ino>, C<st_mode>, C<st_nlink>, C<st_uid>,C<st_gid>, C<st_rdev>, C<st_size>, C<st_atime>, C<st_mtime>, C<st_ctime>
文档解释:如果以前的文件有一点修改，无论是什么属性，都将触发这个回调函数。这个attr文件在这里可以获取到的属性成员有

 1 static void stat_callback(struct ev_loop *loop,ev_stat *w, int revents) 2 { 3     if(w->attr.st_nlink) 4     { 5         printf("The file st_dev %d\n",w->attr.st_dev); 6         printf("The file st_ino %d\n",w->attr.st_ino); 7         printf("The file st_mode %d\n",w->attr.st_mode); 8         printf("The file st_nlink %d\n",w->attr.st_nlink); 9         printf("The file st_uid %d\n",w->attr.st_uid);10         printf("The file st_gid %d\n",w->attr.st_gid);11         printf("The file st_rdev %d\n",w->attr.st_rdev);12         printf("The file st_size %d\n",w->attr.st_size);13         printf("The file st_atime %d\n",w->attr.st_atime);14         printf("The file st_mtime %d\n",w->attr.st_mtime);15         printf("The file st_ctime %d\n",w->attr.st_ctime);16     }17     else18     {19         printf("文件不存在\n");20     }21 }