如何修复将'char [16]'传递给'FILE *'类型的参数（又名'struct __sFILE *'）的不兼容指针类型[-Wincompatible-pointer-types]

Question

怎么修？

警告：

不兼容的指针
类型，将'char [16]'传递给'FILE *'类型的参数
（aka'结构__sFILE *'）[-Wincompatible-pointer-types]
fread（缓冲区，1,512，数据）;
^ ~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/
SDK / MacOSX10.13.sdk / usr / include / stdio.h：247：90：注意：
在此处将参数传递给参数“ __stream”
...__ ptr，size_t __size，size_t __nitems，FILE * __restrict __stream）；
^
产生1条警告。

这是我的代码：

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>

int main()
{

    char readDATA[64];
    char buffer[8];
    char data[16];

    FILE *fl = fopen(data,"r");
    fgets(readDATA,64,fl);
    fread(buffer,1,512,data);
    printf("%s",readDATA);

    return 0;
}

我尝试打开路径或“随机”文件，请帮忙。

Answer 1

根据fread()手册页

函数fread（）从stream指向的流中读取每个长度为字节大小的nmemb数据元素，并将它们存储在ptr给定的位置。

size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);

fread()最后一个参数是FILE *stream ，它表示要从中读取内容并将其存储到buffer 。

更换

 fread(buffer,1,512,data); /* last argument is wrong */

同

fread(buffer,1,512,f1);

还要检查fopen()的返回值

FILE *f1 = fopen("data","r"); /* it will try to open a file called "data" in current working directory, you can take input from user also */
if(f1 == NULL) {
  fprintf(stderr, "file not present\n");
  return 0;
}

你的意图可能是这样

char data[16];/* it doesn't contain anything, so take the input from user or assign directly */
printf("enter the file name\n");
scanf("%s",data);
FILE *f1 = fopen(data,"r"); 
    if(f1 == NULL) {
      fprintf(stderr, "file not present\n");
      return 0;
    }