inotify不注册所有事件

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/inotify.h>
#include <unistd.h>

#define EVENT_SIZE  ( sizeof (struct inotify_event) )
#define BUF_LEN     ( 1024 * ( EVENT_SIZE + 16 ) )

int main( int argc, char **argv ) {
    int length, i = 0;
    int fd;
    int wd;
    char buffer[BUF_LEN];

    fd = inotify_init();
    if ( fd < 0 ) {
        perror( "inotify_init" );
    }

    wd = inotify_add_watch( fd, "/path/to/directory", IN_ACCESS | IN_MODIFY | IN_CREATE | IN_DELETE );
    length = read( fd, buffer, BUF_LEN );

    if ( length < 0 ) {
        perror( "read" );
    }

    while ( i < length ) {
        struct inotify_event *event = ( struct inotify_event * ) &buffer[ i ];
        if ( event->len ) {
            if ( event->mask & IN_ACCESS ) {
                printf( "File %s accessed.\n", event->name );
            }
            if ( event->mask & IN_MODIFY ) {
                printf( "File %s modified.\n", event->name );
            }
            if ( event->mask & IN_CREATE ) {
                printf( "File %s created.\n", event->name );
            }
            if ( event->mask & IN_DELETE ) {
                printf( "File %02d deleted.\n", event->wd );
            }
        }
        i += EVENT_SIZE + event->len;
    }

    ( void ) inotify_rm_watch( fd, wd );
    ( void ) close( fd );

    exit( 0 );
}