int main1(int argc ,char *argv[])
{
if(argc < 2 ) return 0;
int fd = open(argv[1] , O_RDONLY);
if(fd == -1)
{
printf("error is %s
" , strerror(errno));
}
else
{
printf("fd = %d
" ,fd);
char buf[100];
memset(buf , 0, 100);
while(read(fd, buf, sizeof(buf)-1) > 0)//文件大的时候由于buf太小每次只读buf大小, sizeof(buf)-1表示每次不把buff读满留一个作为结尾防止最后一个字节乱码
{
printf("%s
" , buf);
memset(buf , 0, 100);//读完以后清空buf
}
}
close(fd);
return EXIT_SUCCESS;
}
int main(int argc ,char *argv[])
{
char *s = {"abc.txt"};
int fd = open(s, O_RDWR|O_APPEND);//以读写追加的方式
if(fd == -1)
{
printf("error is %s
" , strerror(errno));
}
else
{
printf("sucess fd = %d
" ,fd);
char buf[100];
memset(buf, 0,100);
strcpy(buf,"hello world!
");
int i = write(fd, buf , strlen(buf));
}
close(fd);
return 0;
}