reent.h

标准c库代码,可以应用于各个系统提供了大量的基本函数

/* This header file provides the reentrancy.  */

/* WARNING: All identifiers here must begin with an underscore.  This file is
   included by stdio.h and others and we therefore must only use identifiers
   in the namespace allotted to us.  */

#ifndef _SYS_REENT_H_
#ifdef __cplusplus
extern "C" {
#endif
#define _SYS_REENT_H_

#include <_ansi.h>

#define __need__MAX_SIGNALS
#include <sys/signal.h>     /* for _MAX_SIGNALS */

struct _glue 
{
  struct _glue *_next;
  int _niobs;
  struct __sFILE *_iobs;
};

struct _Bigint 
{
  struct _Bigint *_next;
  int _k, _maxwds, _sign, _wds;
  struct _Bigint *_reclaim;
  unsigned long _x[1];
};

/*
 * atexit() support
 */

#define	_ATEXIT_SIZE 32	/* must be at least 32 to guarantee ANSI conformance */

struct _atexit {
	struct	_atexit *_next;			/* next in list */
	int	_ind;				/* next index in this table */
	void	(*_fns[_ATEXIT_SIZE])();	/* the table itself */
};

/*
 * Stdio buffers.
 *
 * This and __sFILE are defined here because we need them for struct _reent,
 * but we don't want stdio.h included when stdlib.h is.
 */

struct __sbuf {
	unsigned char *_base;
	int	_size;
};

/*
 * We need fpos_t for the following, but it doesn't have a leading "_",
 * so we use _fpos_t instead.
 */

typedef long _fpos_t;		/* XXX must match off_t in <sys/types.h> */
				/* (and must be `long' for now) */

/*
 * Stdio state variables.
 *
 * The following always hold:
 *
 *	if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
 *		_lbfsize is -_bf._size, else _lbfsize is 0
 *	if _flags&__SRD, _w is 0
 *	if _flags&__SWR, _r is 0
 *
 * This ensures that the getc and putc macros (or inline functions) never
 * try to write or read from a file that is in `read' or `write' mode.
 * (Moreover, they can, and do, automatically switch from read mode to
 * write mode, and back, on "r+" and "w+" files.)
 *
 * _lbfsize is used only to make the inline line-buffered output stream
 * code as compact as possible.
 *
 * _ub, _up, and _ur are used when ungetc() pushes back more characters
 * than fit in the current _bf, or when ungetc() pushes back a character
 * that does not match the previous one in _bf.  When this happens,
 * _ub._base becomes non-nil (i.e., a stream has ungetc() data iff
 * _ub._base!=NULL) and _up and _ur save the current values of _p and _r.
 */

struct __sFILE {
  unsigned char *_p;	/* current position in (some) buffer */
  int	_r;		/* read space left for getc() */
  int	_w;		/* write space left for putc() */
  short	_flags;		/* flags, below; this FILE is free if 0 */
  short	_file;		/* fileno, if Unix descriptor, else -1 */
  struct __sbuf _bf;	/* the buffer (at least 1 byte, if !NULL) */
  int	_lbfsize;	/* 0 or -_bf._size, for inline putc */

  /* operations */
  _PTR	_cookie;	/* cookie passed to io functions */

  int	_EXFUN((*_read),(_PTR _cookie, char *_buf, int _n));
  int	_EXFUN((*_write),(_PTR _cookie, const char *_buf, int _n));
  _fpos_t _EXFUN((*_seek),(_PTR _cookie, _fpos_t _offset, int _whence));
  int	_EXFUN((*_close),(_PTR _cookie));

  /* separate buffer for long sequences of ungetc() */
  struct __sbuf _ub;	/* ungetc buffer */
  unsigned char *_up;	/* saved _p when _p is doing ungetc data */
  int	_ur;		/* saved _r when _r is counting ungetc data */

  /* tricks to meet minimum requirements even when malloc() fails */
  unsigned char _ubuf[3];	/* guarantee an ungetc() buffer */
  unsigned char _nbuf[1];	/* guarantee a getc() buffer */

  /* separate buffer for fgetline() when line crosses buffer boundary */
  struct __sbuf _lb;	/* buffer for fgetline() */

  /* Unix stdio files get aligned to block boundaries on fseek() */
  int	_blksize;	/* stat.st_blksize (may be != _bf._size) */
  int	_offset;	/* current lseek offset */

  struct _reent *_data;
};

/*
 * struct _reent
 *
 * This structure contains *all* globals needed by the library.
 * It's raison d'etre is to facilitate threads by making all library routines
 * reentrant.  IE: All state information is contained here.
 */

struct _reent
{
  /* local copy of errno */
  int _errno;

  /* FILE is a big struct and may change over time.  To try to achieve binary
     compatibility with future versions, put stdin,stdout,stderr here.
     These are pointers into member __sf defined below.  */
  struct __sFILE *_stdin, *_stdout, *_stderr;

  char *_scanpoint;		/* used by strtok */
  char _asctime[26];		/* used by asctime */
  long _next;			/* used by rand/srand */
  int  _inc;			/* used by tmpnam */
  char _emergency[25];
 
  int _current_category;	/* used by setlocale */
  _CONST char *_current_locale;

  int __sdidinit;		/* 1 means stdio has been init'd */

  void _EXFUN((*__cleanup),(struct _reent *));

  /* used by mprec routines */
  struct _Bigint *_result;
  int _result_k;
  struct _Bigint *_p5s;
  struct _Bigint **_freelist;

  /* used by gamma */
  int _signgam;

  /* used by some fp conversion routines */
  int _cvtlen;			/* should be size_t */
  char *_cvtbuf;

  /* used by malloc */
#define _N_LISTS 30
  unsigned char * _nextf[_N_LISTS];
  unsigned int _nmalloc[_N_LISTS];

  /* atexit stuff */
  struct _atexit *_atexit;	/* points to head of LIFO stack */
  struct _atexit _atexit0;	/* one guaranteed table, required by ANSI */

  /* These are here last so that __sFILE can grow without changing the offsets
     of the above members (on the off chance that future binary compatibility
     would be broken otherwise).  */
  struct _glue __sglue;			/* root of glue chain */
  struct __sFILE __sf[3];		/* first three file descriptors */

  /* signal info */
   void (**(_sig_func))();
};

#define _REENT_INIT(var) \
  { 0, &var.__sf[0], &var.__sf[1], &var.__sf[2], 0, {0}, 1 }

/*
 * All references to struct _reent are via this pointer.
 * Internally, newlib routines that need to reference it should use _REENT.
 */

extern struct _reent *_impure_ptr;

void _reclaim_reent _PARAMS ((struct _reent *));

/* #define _REENT_ONLY define this to get only reentrant routines */

#ifndef _REENT_ONLY
#define _REENT _impure_ptr
#endif

#ifdef __cplusplus
}
#endif
#endif /* _SYS_REENT_H_ */