//read函数原型：ssize_t read(int fd, void *buf, size_t count);
//lseek函数原型：off_t lseek(int fd, off_t offset, int whence);
SEEK_SET 将光标定位到文件头
SEEK_CUR 光标定位到当前位置
SEEK_END 将光标定位到文件尾部
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
int main()
{
int fd;
char *buf = "ChenLiChen hen shuai!";
fd = open("./file1",O_RDWR);
if(fd == -1){
printf("open file1 failed\n");
fd = open("file1",O_RDWR|O_CREAT,0600);
if(fd > 0){
printf("creat file1 success!\n");
}
}
printf("open success : fd = %d\n",fd);
//ssize_t write(int fd, const void *buf, size_t count);
int n_write = write(fd,buf,strlen(buf));
if(n_write != -1){
printf("write %d byte to file1\n",n_write);
}
char *readBuf; //缓冲区
readBuf = (char *)malloc(sizeof(char)*n_write+1);
//ssize_t read(int fd, void *buf, size_t count);
lseek(fd,0,SEEK_SET); //光标定位到文件头，注意读取文件信息是从光标位置开始读取
int n_read = read(fd,readBuf,n_write);
printf("read %d ,context:%s\n",n_read,readBuf);
close(fd);
return 0;
}
