1.打开流

2.mode参数

3.fopen举例

#include<stdio.h>
int main()
{FILE *fp;fp=fopen("a.txt","r+");if(fp==NULL){printf("fopen error\n");return -1;}return 0;
}

4.新建文件权限

5.处理错误信息

#include<stdio.h>
int main()
{FILE *fp;fp=fopen("a.txt","r+");if(fp==NULL){perror("fopen error\n");return -1;}return 0;
}

#include<stdio.h>
#include<string.h>
#include<errno.h>
int main()
{FILE *fp;fp=fopen("a.txt","r+");if(fp==NULL){printf("fopen:%s\n",strerror(errno));return -1;}return 0;
}

6.关闭流