linux 异步file I/O操作示例

linux 异步file I/O操作示例：

Core dump

 1 #include <sys/types.h>
 2 #include <aio.h>
 3 #include <fcntl.h>
 4 #include <errno.h>
 5 #include <iostream>
 6 
 7 using namespace std;
 8 
 9 const int SIZE_TO_READ = 100;
10 
11 int main()
12 {
13     // open the file
14     int file = open("blah.txt", O_RDONLY, 0);
15     
16     if (file == -1)
17     {
18         cout << "Unable to open file!" << endl;
19         return 1;
20     }
21     
22     // create the buffer
23     char* buffer = new char[SIZE_TO_READ];
24     
25     // create the control block structure
26     aiocb cb;
27     
28     memset(&cb, 0, sizeof(aiocb));
29     cb.aio_nbytes = SIZE_TO_READ;
30     cb.aio_fildes = file;
31     cb.aio_offset = 0;
32     cb.aio_buf = buffer;
33     
34     // read!
35     if (aio_read(&cb) == -1)
36     {
37         cout << "Unable to create request!" << endl;
38         close(file);
39     }
40     
41     cout << "Request enqueued!" << endl;
42     
43     // wait until the request has finished
44     while(aio_error(&cb) == EINPROGRESS)
45     {
46         cout << "Working..." << endl;
47     }
48     
49     // success?
50     int numBytes = aio_return(&cb);
51     
52     if (numBytes != -1)
53         cout << "Success!" << endl;
54     else
55         cout << "Error!" << endl;
56         
57     // now clean up
58     delete[] buffer;
59     close(file);
60     
61     return 0;
62 }

To compile this code you'll most likely need to link to some external library. On Linux use -lrt, and on OSX it's -lc.

参考：

http://fwheel.net/aio.html