c - 如何将包含已分配内存的结构保存到文件？

Question

// Headers

struct Address{
  int id;
  char *name;
  char *email;
};

struct Database{
  struct Address *rows;
  int max_size;
  int max_data;
};

struct Connection{
  FILE *file;
  struct Database *db; 
};

int main(int argc, char *argv[]){
  int i;
  struct Connection *conn;

  conn->file = fopen(argv[3], "w+");
  conn->db->max_size = atoi(argv[1]);
  conn->db->max_data = atoi(argv[2]);

  conn->db->rows = malloc(sizeof(struct Address) * (db->max_size));

  for(i=0; i<db->max_size; i++){
    struct Address adr = {.id = i};
    adr.name = malloc(conn->db->max_data);
    adr.email = malloc(conn->db->max_data);

    conn->db->rows[i] = addr;
  }

  /* Other CODE(s) here
   *
   *
  */
}

现在，根据这些代码片段，如何将 conn->db 结构保存到 conn->file 中并包含所有内容？之后，我必须能够再次从文件中读取它。

我无法使用堆栈类型结构，因为“ma​​x_data”和“ma​​x_size”是用户输入的!

Answer 1

您是否考虑过写入二进制文件。

用于写作

FILE *write_ptr;

write_ptr = fopen("test.bin","wb");  // w for write, b for binary
fwrite(conn->db,sizeof(conn->db),1,write_ptr); // write number of bytes determined by the structure size into a binary file

用于读取该文件

FILE *read_ptr;

read_ptr = fopen("test.bin","rb");  // r for read, b for binary
fread(conn->db,sizeof(conn-db),1,ptr); // read bytes determined by size of structure form the file into the current conn->db structure 

请注意，二进制文件无法在painttext中打开和读取