linux 异步file I/O操作示例

linux 异步file I/O操作示例：

Core dump

#include <sys/types.h>
#include <aio.h>
#include <fcntl.h>
#include <errno.h>
#include <iostream>

using namespace std;

const int SIZE_TO_READ = 100;

int main()
{
    // open the file
    int file = open("blah.txt", O_RDONLY, 0);
    
    if (file == -1)
    {
        cout << "Unable to open file!" << endl;
        return 1;
    }
    
    // create the buffer
    char* buffer = new char[SIZE_TO_READ];
    
    // create the control block structure
    aiocb cb;
    
    memset(&cb, 0, sizeof(aiocb));
    cb.aio_nbytes = SIZE_TO_READ;
    cb.aio_fildes = file;
    cb.aio_offset = 0;
    cb.aio_buf = buffer;
    
    // read!
    if (aio_read(&cb) == -1)
    {
        cout << "Unable to create request!" << endl;
        close(file);
    }
    
    cout << "Request enqueued!" << endl;
    
    // wait until the request has finished
    while(aio_error(&cb) == EINPROGRESS)
    {
        cout << "Working..." << endl;
    }
    
    // success?
    int numBytes = aio_return(&cb);
    
    if (numBytes != -1)
        cout << "Success!" << endl;
    else
        cout << "Error!" << endl;
        
    // now clean up
    delete[] buffer;
    close(file);
    
    return 0;
}

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