linux AIO 读文件实例
AIO读操作,使用系统调用实现
#define BUFSIZE 1024#include <stdio.h>#include <stdlib.h>#include <aio.h>#include <errno.h>#include <unistd.h>#include <string.h>int main(void) {int fd, ret;struct aiocb my_aiocb;fd = open("file.txt", O_RDONLY);if (fd < 0)perror("open");/* Zero out the aiocb structure (recommended) */bzero((char *) &my_aiocb, sizeof(struct aiocb));/* Allocate a data buffer for the aiocb request */my_aiocb.aio_buf = malloc(BUFSIZE + 1);if (!my_aiocb.aio_buf)perror("malloc");/* Initialize the necessary fields in the aiocb */my_aiocb.aio_fildes = fd;my_aiocb.aio_nbytes = BUFSIZE;my_aiocb.aio_offset = 0;ret = aio_read(&my_aiocb);if (ret < 0)perror("aio_read");/** aio_error return value : EINPROGRESS，说明请求尚未完成 ECANCELLED，说明请求被应用程序取消了 -1，说明发生了错误，具体错误原因可以查阅 errno.h */while (aio_error(&my_aiocb) == EINPROGRESS);if ((ret = aio_return(&my_aiocb)) > 0) {/* got ret bytes on the read */ int n = my_aiocb.aio_nbytes; //length char *p0=(char *)my_aiocb.aio_buf; //返回字符 printf("p0 is %s\n",p0);puts("!read success!!!");printf("buffersize is %d,real byte size is %d", n, ret);} else {/* read failed, consult errno */puts("!!!read fail!!");}return 0;}?
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这样建立一个测试文件，就可以异步读取了，使用gcc编译的时候注意链接动态库librt编译命令如下：
gcc -o myaio ?myaio.c /lib/librt.so.1
librt.so.1为我的rt动态链接库，在/lib目录下