操作系统接口，打开文件的句柄
OS Interface Open File Handle

typedef struct sqlite3_file sqlite3_file;
struct sqlite3_file {
  const struct sqlite3_io_methods *pMethods;  /* 一个打开文件的方法。Methods for an open file */
};

在操作系统接口层，sqlite3_file对象表示一个打开的文件。不同的操作系统实现会创建这个类的子类，追加一些自己使用的字段。pMethods是一个指向sqlite3_io_methods对象的指针，它定义了在打开的文件上执行I/O操作的方法。
An sqlite3_file object represents an open file in the OS interface layer. Individual OS interface implementations will want to subclass this object by appending additional fields for their own use. The pMethods entry is a pointer to an sqlite3_io_methods object that defines methods for performing I/O operations on the open file.

另行参见Objects、Constants和Functions的列表。
See also lists of Objects, Constants, and Functions.