FILE 的结构
typedef struct _iobuf
...{
char *_ptr; // pointer to next character position int _cnt; // number of characters left in buffer char *_base; // pointer to start of buffer int _flag; //various info about this channel int _file; //file "handle" unsigned _bufsiz; //size of buffer being used #ifdef BIGBUF int _seg;
/**//* segment of buffer if _IOBIGBUF */#endif
}FILE;