如何在成员初始化列表中调用函数?

jpeg_create_decompress() jpeg_decompress_struct

jpeg_decompress_struct make_initialized_jds() {
  jpeg_decompress_struct result;
  jpeg_create_decompress(&result);
  return result;
}

class Decompress {
  typedef jpeg_decompress_struct *ptr;
  jpeg_decompress_struct srcinfo;

 public:
  Decompress() : srcinfo(make_initialized_jds()) {}
  ~Decompress() { jpeg_destroy_decompress(&srcinfo); }
  operator ptr() { return &srcinfo; }
  jpeg_decompress_struct *operator->() { return &srcinfo; }
};

根据更新后的问题:如果您只是想消除警告,可以使用成员初始化来明确初始化结构:

class Decompress {
  typedef jpeg_decompress_struct *ptr = nullptr; // <---- might as well. 
  jpeg_decompress_struct srcinfo = {0}; // <----- here

 public:
  Decompress() { jpeg_create_decompress(&srcinfo); }
  ~Decompress() { jpeg_destroy_decompress(&srcinfo); }
  operator ptr() { return &srcinfo; }
  jpeg_decompress_struct *operator->() { return &srcinfo; }
};

这将给 srcinfo 调用之前定义的值