Unix中文件(FILE)的定义在哪里?

5

我知道FILE是一个typedef-ed结构体,但我在哪里可以查找struct FILE的实际定义,使用man页?


查看 /usr/include/libio.h 中的 struct _IO_FILE - perreal
1个回答

8
如果您从/usr/include/stdio.h开始查找,会发现这样一行代码:
typedef struct _IO_FILE FILE;

只需在 /usr/include 中搜索 __IO_FILE,就可以发现这个结构体的定义在 /usr/include/libio.h 中。

我的 /usr/include/libio.h 显示了以下关于 __IO_FILE 的定义:

struct _IO_FILE {
  int _flags;       /* High-order word is _IO_MAGIC; rest is flags. */
#define _IO_file_flags _flags

  /* The following pointers correspond to the C++ streambuf protocol. */
  /* Note:  Tk uses the _IO_read_ptr and _IO_read_end fields directly. */
  char* _IO_read_ptr;   /* Current read pointer */
  char* _IO_read_end;   /* End of get area. */
  char* _IO_read_base;  /* Start of putback+get area. */
  char* _IO_write_base; /* Start of put area. */
  char* _IO_write_ptr;  /* Current put pointer. */
  char* _IO_write_end;  /* End of put area. */
  char* _IO_buf_base;   /* Start of reserve area. */
  char* _IO_buf_end;    /* End of reserve area. */
  /* The following fields are used to support backing up and undo. */
  char *_IO_save_base; /* Pointer to start of non-current get area. */
  char *_IO_backup_base;  /* Pointer to first valid character of backup area */
  char *_IO_save_end; /* Pointer to end of non-current get area. */

  struct _IO_marker *_markers;

  struct _IO_FILE *_chain;

  int _fileno;
#if 0
  int _blksize;
#else
  int _flags2;
#endif
  _IO_off_t _old_offset; /* This used to be _offset but it's too small.  */

#define __HAVE_COLUMN /* temporary */
  /* 1+column number of pbase(); 0 is unknown. */
  unsigned short _cur_column;
  signed char _vtable_offset;
  char _shortbuf[1];

  /*  char* _save_gptr;  char* _save_egptr; */

  _IO_lock_t *_lock;
#ifdef _IO_USE_OLD_IO_FILE
};

struct _IO_FILE_complete
{
  struct _IO_FILE _file;
#endif
#if defined _G_IO_IO_FILE_VERSION && _G_IO_IO_FILE_VERSION == 0x20001
  _IO_off64_t _offset;
# if defined _LIBC || defined _GLIBCPP_USE_WCHAR_T
  /* Wide character stream stuff.  */
  struct _IO_codecvt *_codecvt;
  struct _IO_wide_data *_wide_data;
  struct _IO_FILE *_freeres_list;
  void *_freeres_buf;
  size_t _freeres_size;
# else
  void *__pad1;
  void *__pad2;
  void *__pad3;
  void *__pad4;
  size_t __pad5;
# endif
  int _mode;
  /* Make sure we don't get into trouble again.  */
  char _unused2[15 * sizeof (int) - 4 * sizeof (void *) - sizeof (size_t)];
#endif
};

6
回答不错,但我想补充一点,FILE 是一种被称为不透明类型的类型。你不应该查看它的定义;它是供 C 标准库内部使用的,其他代码不应该查看其内部细节。细节在各个平台和版本之间会有很大差异。 - Ernest Friedman-Hill
@ErnestFriedman-Hill,我喜欢你对_opaque type_的解释。 - SIFE

网页内容由stack overflow 提供, 点击上面的
可以查看英文原文,
原文链接