我希望我的程序等待几秒钟以允许目录/文件更改,这样如果满足一个条件并且执行代码,事件循环保持打开状态以允许更多文件/目录更改,但我现在只在一个事件后退出循环运行。我遇到了 select() 系统调用,但我不知道如何插入到我的程序中以实现我的目标,
下面是我在 http://www.thegeekstuff.com/2010/04/inotify-c-program-example/ 上找到的一段代码,可能有助于说明我想要做的事情(我的 while 循环比这里的它看起来不会难看)
/*This is the sample program to notify us for the file creation and file deletion takes place in “/tmp” directory*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <linux/inotify.h>
#define EVENT_SIZE ( sizeof (struct inotify_event) )
#define EVENT_BUF_LEN ( 1024 * ( EVENT_SIZE + 16 ) )
int main( )
{
int length, i = 0;
int fd;
int wd;
char buffer[EVENT_BUF_LEN];
/*creating the INOTIFY instance*/
fd = inotify_init();
/*checking for error*/
if ( fd < 0 ) {
perror( "inotify_init" );
}
/*adding the “/tmp” directory into watch list. Here, the suggestion is to validate the existence of the directory before adding into monitoring list.*/
wd = inotify_add_watch( fd, "/tmp/foo", IN_CREATE | IN_DELETE );
/*read to determine the event change happens on “/tmp” directory. Actually this read blocks until the change event occurs*/
length = read( fd, buffer, EVENT_BUF_LEN );
/*checking for error*/
if ( length < 0 ) {
perror( "read" );
}
/*actually read return the list of change events happens. Here, read the change event one by one and process it accordingly.*/
while ( i < length ) {
struct inotify_event *event = ( struct inotify_event * ) &buffer[ i ];
if ( event->len ) {
if ( event->mask & IN_CREATE ) {
if ( event->mask & IN_ISDIR ) {
printf( "New directory %s created.\n", event->name );
}
else {
printf( "New file %s created.\n", event->name );
}
}
else if ( event->mask & IN_DELETE ) {
if ( event->mask & IN_ISDIR ) {
printf( "Directory %s deleted.\n", event->name );
}
else {
printf( "File %s deleted.\n", event->name );
}
}
}
i += EVENT_SIZE + event->len;
}
/*removing the “/tmp” directory from the watch list.*/
inotify_rm_watch( fd, wd );
/*closing the INOTIFY instance*/
close( fd );
}
如果我理解正确,看起来您可以简单地将
read()
和 while()
语句放在循环中。例如
while ((length = read(...)) >= 0) {
while (i < length) {
...
}
}
read()
将阻塞,直到有可用的东西为止。