print.c

/* Lisp object printing and output streams.
   Copyright (C) 1985, 1986, 1988, 1993, 1994, 1995, 1997,
                 1998, 1999, 2000, 2001, 2002, 2003, 2004,
                 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */


#include <config.h>
#include <stdio.h>
#include <setjmp.h>
#include "lisp.h"
#include "buffer.h"
#include "character.h"
#include "charset.h"
#include "keyboard.h"
#include "frame.h"
#include "window.h"
#include "process.h"
#include "dispextern.h"
#include "termchar.h"
#include "intervals.h"
#include "blockinput.h"
#include "termhooks.h"		/* For struct terminal.  */
#include "font.h"

Lisp_Object Vstandard_output, Qstandard_output;

Lisp_Object Qtemp_buffer_setup_hook;

/* These are used to print like we read.  */

Lisp_Object Vfloat_output_format, Qfloat_output_format;

#include <math.h>

#if STDC_HEADERS
#include <float.h>
#endif

/* Default to values appropriate for IEEE floating point.  */
#ifndef FLT_RADIX
#define FLT_RADIX 2
#endif
#ifndef DBL_MANT_DIG
#define DBL_MANT_DIG 53
#endif
#ifndef DBL_DIG
#define DBL_DIG 15
#endif
#ifndef DBL_MIN
#define DBL_MIN 2.2250738585072014e-308
#endif

#ifdef DBL_MIN_REPLACEMENT
#undef DBL_MIN
#define DBL_MIN DBL_MIN_REPLACEMENT
#endif

/* Define DOUBLE_DIGITS_BOUND, an upper bound on the number of decimal digits
   needed to express a float without losing information.
   The general-case formula is valid for the usual case, IEEE floating point,
   but many compilers can't optimize the formula to an integer constant,
   so make a special case for it.  */
#if FLT_RADIX == 2 && DBL_MANT_DIG == 53
#define DOUBLE_DIGITS_BOUND 17 /* IEEE floating point */
#else
#define DOUBLE_DIGITS_BOUND ((int) ceil (log10 (pow (FLT_RADIX, DBL_MANT_DIG))))
#endif

/* Avoid actual stack overflow in print.  */
int print_depth;

/* Level of nesting inside outputting backquote in new style.  */
int new_backquote_output;

/* Detect most circularities to print finite output.  */
#define PRINT_CIRCLE 200
Lisp_Object being_printed[PRINT_CIRCLE];

/* When printing into a buffer, first we put the text in this
   block, then insert it all at once.  */
char *print_buffer;

/* Size allocated in print_buffer.  */
EMACS_INT print_buffer_size;
/* Chars stored in print_buffer.  */
EMACS_INT print_buffer_pos;
/* Bytes stored in print_buffer.  */
EMACS_INT print_buffer_pos_byte;

/* Maximum length of list to print in full; noninteger means
   effectively infinity */

Lisp_Object Vprint_length;

/* Maximum depth of list to print in full; noninteger means
   effectively infinity.  */

Lisp_Object Vprint_level;

/* Nonzero means print newlines in strings as \n.  */

int print_escape_newlines;

/* Nonzero means to print single-byte non-ascii characters in strings as
   octal escapes.  */

int print_escape_nonascii;

/* Nonzero means to print multibyte characters in strings as hex escapes.  */

int print_escape_multibyte;

Lisp_Object Qprint_escape_newlines;
Lisp_Object Qprint_escape_multibyte, Qprint_escape_nonascii;

/* Nonzero means print (quote foo) forms as 'foo, etc.  */

int print_quoted;

/* Non-nil means print #: before uninterned symbols.  */

Lisp_Object Vprint_gensym;

/* Non-nil means print recursive structures using #n= and #n# syntax.  */

Lisp_Object Vprint_circle;

/* Non-nil means keep continuous number for #n= and #n# syntax
   between several print functions.  */

Lisp_Object Vprint_continuous_numbering;

/* Vprint_number_table is a table, that keeps objects that are going to
   be printed, to allow use of #n= and #n# to express sharing.
   For any given object, the table can give the following values:
     t    the object will be printed only once.
     -N   the object will be printed several times and will take number N.
     N    the object has been printed so we can refer to it as #N#.
   print_number_index holds the largest N already used.
   N has to be striclty larger than 0 since we need to distinguish -N.  */
int print_number_index;
Lisp_Object Vprint_number_table;

void print_interval (INTERVAL interval, Lisp_Object printcharfun);

/* GDB resets this to zero on W32 to disable OutputDebugString calls.  */
int print_output_debug_flag EXTERNALLY_VISIBLE = 1;


/* Low level output routines for characters and strings */

/* Lisp functions to do output using a stream
   must have the stream in a variable called printcharfun
   and must start with PRINTPREPARE, end with PRINTFINISH,
   and use PRINTDECLARE to declare common variables.
   Use PRINTCHAR to output one character,
   or call strout to output a block of characters. */

#define PRINTDECLARE							\
   struct buffer *old = current_buffer;					\
   EMACS_INT old_point = -1, start_point = -1;				\
   EMACS_INT old_point_byte = -1, start_point_byte = -1;		\
   int specpdl_count = SPECPDL_INDEX ();				\
   int free_print_buffer = 0;						\
   int multibyte = !NILP (current_buffer->enable_multibyte_characters);	\
   Lisp_Object original

#define PRINTPREPARE							\
   original = printcharfun;						\
   if (NILP (printcharfun)) printcharfun = Qt;				\
   if (BUFFERP (printcharfun))						\
     {									\
       if (XBUFFER (printcharfun) != current_buffer)			\
	 Fset_buffer (printcharfun);					\
       printcharfun = Qnil;						\
     }									\
   if (MARKERP (printcharfun))						\
     {									\
       EMACS_INT marker_pos;						\
       if (! XMARKER (printcharfun)->buffer)				\
         error ("Marker does not point anywhere");			\
       if (XMARKER (printcharfun)->buffer != current_buffer)		\
         set_buffer_internal (XMARKER (printcharfun)->buffer);		\
       marker_pos = marker_position (printcharfun);			\
       if (marker_pos < BEGV || marker_pos > ZV)			\
	 error ("Marker is outside the accessible part of the buffer"); \
       old_point = PT;							\
       old_point_byte = PT_BYTE;					\
       SET_PT_BOTH (marker_pos,						\
		    marker_byte_position (printcharfun));		\
       start_point = PT;						\
       start_point_byte = PT_BYTE;					\
       printcharfun = Qnil;						\
     }									\
   if (NILP (printcharfun))						\
     {									\
       Lisp_Object string;						\
       if (NILP (current_buffer->enable_multibyte_characters)		\
	   && ! print_escape_multibyte)					\
         specbind (Qprint_escape_multibyte, Qt);			\
       if (! NILP (current_buffer->enable_multibyte_characters)		\
	   && ! print_escape_nonascii)					\
         specbind (Qprint_escape_nonascii, Qt);				\
       if (print_buffer != 0)						\
	 {								\
	   string = make_string_from_bytes (print_buffer,		\
					    print_buffer_pos,		\
					    print_buffer_pos_byte);	\
	   record_unwind_protect (print_unwind, string);		\
	 }								\
       else								\
	 {								\
           print_buffer_size = 1000;					\
           print_buffer = (char *) xmalloc (print_buffer_size);		\
	   free_print_buffer = 1;					\
	 }								\
       print_buffer_pos = 0;						\
       print_buffer_pos_byte = 0;					\
     }									\
   if (EQ (printcharfun, Qt) && ! noninteractive)			\
     setup_echo_area_for_printing (multibyte);

#define PRINTFINISH							\
   if (NILP (printcharfun))						\
     {									\
       if (print_buffer_pos != print_buffer_pos_byte			\
	   && NILP (current_buffer->enable_multibyte_characters))	\
	 {								\
	   unsigned char *temp						\
	     = (unsigned char *) alloca (print_buffer_pos + 1);		\
	   copy_text (print_buffer, temp, print_buffer_pos_byte,	\
		      1, 0);						\
	   insert_1_both (temp, print_buffer_pos,			\
			  print_buffer_pos, 0, 1, 0);			\
	 }								\
       else								\
	 insert_1_both (print_buffer, print_buffer_pos,			\
			print_buffer_pos_byte, 0, 1, 0);		\
       signal_after_change (PT - print_buffer_pos, 0, print_buffer_pos);\
     }									\
   if (free_print_buffer)						\
     {									\
       xfree (print_buffer);						\
       print_buffer = 0;						\
     }									\
   unbind_to (specpdl_count, Qnil);					\
   if (MARKERP (original))						\
     set_marker_both (original, Qnil, PT, PT_BYTE);			\
   if (old_point >= 0)							\
     SET_PT_BOTH (old_point + (old_point >= start_point			\
			       ? PT - start_point : 0),			\
		  old_point_byte + (old_point_byte >= start_point_byte	\
				    ? PT_BYTE - start_point_byte : 0));	\
   if (old != current_buffer)						\
     set_buffer_internal (old);

#define PRINTCHAR(ch) printchar (ch, printcharfun)

/* This is used to restore the saved contents of print_buffer
   when there is a recursive call to print.  */

static Lisp_Object
print_unwind (Lisp_Object saved_text)
{
  memcpy (print_buffer, SDATA (saved_text), SCHARS (saved_text));
  return Qnil;
}


/* Print character CH using method FUN.  FUN nil means print to
   print_buffer.  FUN t means print to echo area or stdout if
   non-interactive.  If FUN is neither nil nor t, call FUN with CH as
   argument.  */

static void
printchar (unsigned int ch, Lisp_Object fun)
{
  if (!NILP (fun) && !EQ (fun, Qt))
    call1 (fun, make_number (ch));
  else
    {
      unsigned char str[MAX_MULTIBYTE_LENGTH];
      int len = CHAR_STRING (ch, str);

      QUIT;

      if (NILP (fun))
	{
	  if (print_buffer_pos_byte + len >= print_buffer_size)
	    print_buffer = (char *) xrealloc (print_buffer,
					      print_buffer_size *= 2);
	  memcpy (print_buffer + print_buffer_pos_byte, str, len);
	  print_buffer_pos += 1;
	  print_buffer_pos_byte += len;
	}
      else if (noninteractive)
	{
	  fwrite (str, 1, len, stdout);
	  noninteractive_need_newline = 1;
	}
      else
	{
	  int multibyte_p
	    = !NILP (current_buffer->enable_multibyte_characters);

	  setup_echo_area_for_printing (multibyte_p);
	  insert_char (ch);
	  message_dolog (str, len, 0, multibyte_p);
	}
    }
}


/* Output SIZE characters, SIZE_BYTE bytes from string PTR using
   method PRINTCHARFUN.  If SIZE < 0, use the string length of PTR for
   both SIZE and SIZE_BYTE.  PRINTCHARFUN nil means output to
   print_buffer.  PRINTCHARFUN t means output to the echo area or to
   stdout if non-interactive.  If neither nil nor t, call Lisp
   function PRINTCHARFUN for each character printed.  MULTIBYTE
   non-zero means PTR contains multibyte characters.

   In the case where PRINTCHARFUN is nil, it is safe for PTR to point
   to data in a Lisp string.  Otherwise that is not safe.  */

static void
strout (const char *ptr, EMACS_INT size, EMACS_INT size_byte,
	Lisp_Object printcharfun, int multibyte)
{
  if (size < 0)
    size_byte = size = strlen (ptr);

  if (NILP (printcharfun))
    {
      if (print_buffer_pos_byte + size_byte > print_buffer_size)
	{
	  print_buffer_size = print_buffer_size * 2 + size_byte;
	  print_buffer = (char *) xrealloc (print_buffer,
					    print_buffer_size);
	}
      memcpy (print_buffer + print_buffer_pos_byte, ptr, size_byte);
      print_buffer_pos += size;
      print_buffer_pos_byte += size_byte;
    }
  else if (noninteractive && EQ (printcharfun, Qt))
    {
      fwrite (ptr, 1, size_byte, stdout);
      noninteractive_need_newline = 1;
    }
  else if (EQ (printcharfun, Qt))
    {
      /* Output to echo area.  We're trying to avoid a little overhead
	 here, that's the reason we don't call printchar to do the
	 job.  */
      int i;
      int multibyte_p
	= !NILP (current_buffer->enable_multibyte_characters);

      setup_echo_area_for_printing (multibyte_p);
      message_dolog (ptr, size_byte, 0, multibyte_p);

      if (size == size_byte)
	{
	  for (i = 0; i < size; ++i)
	    insert_char ((unsigned char) *ptr++);
	}
      else
	{
	  int len;
	  for (i = 0; i < size_byte; i += len)
	    {
	      int ch = STRING_CHAR_AND_LENGTH (ptr + i, len);
	      insert_char (ch);
	    }
	}
    }
  else
    {
      /* PRINTCHARFUN is a Lisp function.  */
      EMACS_INT i = 0;

      if (size == size_byte)
	{
	  while (i < size_byte)
	    {
	      int ch = ptr[i++];
	      PRINTCHAR (ch);
	    }
	}
      else
	{
	  while (i < size_byte)
	    {
	      /* Here, we must convert each multi-byte form to the
		 corresponding character code before handing it to
		 PRINTCHAR.  */
	      int len;
	      int ch = STRING_CHAR_AND_LENGTH (ptr + i, len);
	      PRINTCHAR (ch);
	      i += len;
	    }
	}
    }
}

/* Print the contents of a string STRING using PRINTCHARFUN.
   It isn't safe to use strout in many cases,
   because printing one char can relocate.  */

static void
print_string (Lisp_Object string, Lisp_Object printcharfun)
{
  if (EQ (printcharfun, Qt) || NILP (printcharfun))
    {
      EMACS_INT chars;

      if (print_escape_nonascii)
	string = string_escape_byte8 (string);

      if (STRING_MULTIBYTE (string))
	chars = SCHARS (string);
      else if (! print_escape_nonascii
	       && (EQ (printcharfun, Qt)
		   ? ! NILP (buffer_defaults.enable_multibyte_characters)
		   : ! NILP (current_buffer->enable_multibyte_characters)))
	{
	  /* If unibyte string STRING contains 8-bit codes, we must
	     convert STRING to a multibyte string containing the same
	     character codes.  */
	  Lisp_Object newstr;
	  EMACS_INT bytes;

	  chars = SBYTES (string);
	  bytes = parse_str_to_multibyte (SDATA (string), chars);
	  if (chars < bytes)
	    {
	      newstr = make_uninit_multibyte_string (chars, bytes);
	      memcpy (SDATA (newstr), SDATA (string), chars);
	      str_to_multibyte (SDATA (newstr), bytes, chars);
	      string = newstr;
	    }
	}
      else
	chars = SBYTES (string);

      if (EQ (printcharfun, Qt))
	{
	  /* Output to echo area.  */
	  EMACS_INT nbytes = SBYTES (string);
	  char *buffer;

	  /* Copy the string contents so that relocation of STRING by
	     GC does not cause trouble.  */
	  USE_SAFE_ALLOCA;

	  SAFE_ALLOCA (buffer, char *, nbytes);
	  memcpy (buffer, SDATA (string), nbytes);

	  strout (buffer, chars, SBYTES (string),
		  printcharfun, STRING_MULTIBYTE (string));

	  SAFE_FREE ();
	}
      else
	/* No need to copy, since output to print_buffer can't GC.  */
	strout (SDATA (string),
		chars, SBYTES (string),
		printcharfun, STRING_MULTIBYTE (string));
    }
  else
    {
      /* Otherwise, string may be relocated by printing one char.
	 So re-fetch the string address for each character.  */
      EMACS_INT i;
      EMACS_INT size = SCHARS (string);
      EMACS_INT size_byte = SBYTES (string);
      struct gcpro gcpro1;
      GCPRO1 (string);
      if (size == size_byte)
	for (i = 0; i < size; i++)
	  PRINTCHAR (SREF (string, i));
      else
	for (i = 0; i < size_byte; )
	  {
	    /* Here, we must convert each multi-byte form to the
	       corresponding character code before handing it to PRINTCHAR.  */
	    int len;
	    int ch = STRING_CHAR_AND_LENGTH (SDATA (string) + i, len);
	    PRINTCHAR (ch);
	    i += len;
	  }
      UNGCPRO;
    }
}

DEFUN ("write-char", Fwrite_char, Swrite_char, 1, 2, 0,
       doc: /* Output character CHARACTER to stream PRINTCHARFUN.
PRINTCHARFUN defaults to the value of `standard-output' (which see).  */)
  (Lisp_Object character, Lisp_Object printcharfun)
{
  PRINTDECLARE;

  if (NILP (printcharfun))
    printcharfun = Vstandard_output;
  CHECK_NUMBER (character);
  PRINTPREPARE;
  PRINTCHAR (XINT (character));
  PRINTFINISH;
  return character;
}

/* Used from outside of print.c to print a block of SIZE
   single-byte chars at DATA on the default output stream.
   Do not use this on the contents of a Lisp string.  */

void
write_string (const char *data, int size)
{
  PRINTDECLARE;
  Lisp_Object printcharfun;

  printcharfun = Vstandard_output;

  PRINTPREPARE;
  strout (data, size, size, printcharfun, 0);
  PRINTFINISH;
}

/* Used to print a block of SIZE single-byte chars at DATA on a
   specified stream PRINTCHARFUN.
   Do not use this on the contents of a Lisp string.  */

static void
write_string_1 (const char *data, int size, Lisp_Object printcharfun)
{
  PRINTDECLARE;

  PRINTPREPARE;
  strout (data, size, size, printcharfun, 0);
  PRINTFINISH;
}


void
temp_output_buffer_setup (const char *bufname)
{
  int count = SPECPDL_INDEX ();
  register struct buffer *old = current_buffer;
  register Lisp_Object buf;

  record_unwind_protect (set_buffer_if_live, Fcurrent_buffer ());

  Fset_buffer (Fget_buffer_create (build_string (bufname)));

  Fkill_all_local_variables ();
  delete_all_overlays (current_buffer);
  current_buffer->directory = old->directory;
  current_buffer->read_only = Qnil;
  current_buffer->filename = Qnil;
  current_buffer->undo_list = Qt;
  eassert (current_buffer->overlays_before == NULL);
  eassert (current_buffer->overlays_after == NULL);
  current_buffer->enable_multibyte_characters
    = buffer_defaults.enable_multibyte_characters;
  specbind (Qinhibit_read_only, Qt);
  specbind (Qinhibit_modification_hooks, Qt);
  Ferase_buffer ();
  XSETBUFFER (buf, current_buffer);

  Frun_hooks (1, &Qtemp_buffer_setup_hook);

  unbind_to (count, Qnil);

  specbind (Qstandard_output, buf);
}

Lisp_Object
internal_with_output_to_temp_buffer (const char *bufname, Lisp_Object (*function) (Lisp_Object), Lisp_Object args)
{
  int count = SPECPDL_INDEX ();
  Lisp_Object buf, val;
  struct gcpro gcpro1;

  GCPRO1 (args);
  record_unwind_protect (Fset_buffer, Fcurrent_buffer ());
  temp_output_buffer_setup (bufname);
  buf = Vstandard_output;
  UNGCPRO;

  val = (*function) (args);

  GCPRO1 (val);
  temp_output_buffer_show (buf);
  UNGCPRO;

  return unbind_to (count, val);
}

DEFUN ("with-output-to-temp-buffer",
       Fwith_output_to_temp_buffer, Swith_output_to_temp_buffer,
       1, UNEVALLED, 0,
       doc: /* Bind `standard-output' to buffer BUFNAME, eval BODY, then show that buffer.

This construct makes buffer BUFNAME empty before running BODY.
It does not make the buffer current for BODY.
Instead it binds `standard-output' to that buffer, so that output
generated with `prin1' and similar functions in BODY goes into
the buffer.

At the end of BODY, this marks buffer BUFNAME unmodifed and displays
it in a window, but does not select it.  The normal way to do this is
by calling `display-buffer', then running `temp-buffer-show-hook'.
However, if `temp-buffer-show-function' is non-nil, it calls that
function instead (and does not run `temp-buffer-show-hook').  The
function gets one argument, the buffer to display.

The return value of `with-output-to-temp-buffer' is the value of the
last form in BODY.  If BODY does not finish normally, the buffer
BUFNAME is not displayed.

This runs the hook `temp-buffer-setup-hook' before BODY,
with the buffer BUFNAME temporarily current.  It runs the hook
`temp-buffer-show-hook' after displaying buffer BUFNAME, with that
buffer temporarily current, and the window that was used to display it
temporarily selected.  But it doesn't run `temp-buffer-show-hook'
if it uses `temp-buffer-show-function'.

usage: (with-output-to-temp-buffer BUFNAME BODY...)  */)
  (Lisp_Object args)
{
  struct gcpro gcpro1;
  Lisp_Object name;
  int count = SPECPDL_INDEX ();
  Lisp_Object buf, val;

  GCPRO1(args);
  name = Feval (Fcar (args));
  CHECK_STRING (name);
  temp_output_buffer_setup (SDATA (name));
  buf = Vstandard_output;
  UNGCPRO;

  val = Fprogn (XCDR (args));

  GCPRO1 (val);
  temp_output_buffer_show (buf);
  UNGCPRO;

  return unbind_to (count, val);
}


static void print (Lisp_Object obj, register Lisp_Object printcharfun, int escapeflag);
static void print_preprocess (Lisp_Object obj);
static void print_preprocess_string (INTERVAL interval, Lisp_Object arg);
static void print_object (Lisp_Object obj, register Lisp_Object printcharfun, int escapeflag);

DEFUN ("terpri", Fterpri, Sterpri, 0, 1, 0,
       doc: /* Output a newline to stream PRINTCHARFUN.
If PRINTCHARFUN is omitted or nil, the value of `standard-output' is used.  */)
  (Lisp_Object printcharfun)
{
  PRINTDECLARE;

  if (NILP (printcharfun))
    printcharfun = Vstandard_output;
  PRINTPREPARE;
  PRINTCHAR ('\n');
  PRINTFINISH;
  return Qt;
}

DEFUN ("prin1", Fprin1, Sprin1, 1, 2, 0,
       doc: /* Output the printed representation of OBJECT, any Lisp object.
Quoting characters are printed when needed to make output that `read'
can handle, whenever this is possible.  For complex objects, the behavior
is controlled by `print-level' and `print-length', which see.

OBJECT is any of the Lisp data types: a number, a string, a symbol,
a list, a buffer, a window, a frame, etc.

A printed representation of an object is text which describes that object.

Optional argument PRINTCHARFUN is the output stream, which can be one
of these:

   - a buffer, in which case output is inserted into that buffer at point;
   - a marker, in which case output is inserted at marker's position;
   - a function, in which case that function is called once for each
     character of OBJECT's printed representation;
   - a symbol, in which case that symbol's function definition is called; or
   - t, in which case the output is displayed in the echo area.

If PRINTCHARFUN is omitted, the value of `standard-output' (which see)
is used instead.  */)
  (Lisp_Object object, Lisp_Object printcharfun)
{
  PRINTDECLARE;

  if (NILP (printcharfun))
    printcharfun = Vstandard_output;
  PRINTPREPARE;
  print (object, printcharfun, 1);
  PRINTFINISH;
  return object;
}

/* a buffer which is used to hold output being built by prin1-to-string */
Lisp_Object Vprin1_to_string_buffer;

DEFUN ("prin1-to-string", Fprin1_to_string, Sprin1_to_string, 1, 2, 0,
       doc: /* Return a string containing the printed representation of OBJECT.
OBJECT can be any Lisp object.  This function outputs quoting characters
when necessary to make output that `read' can handle, whenever possible,
unless the optional second argument NOESCAPE is non-nil.  For complex objects,
the behavior is controlled by `print-level' and `print-length', which see.

OBJECT is any of the Lisp data types: a number, a string, a symbol,
a list, a buffer, a window, a frame, etc.

A printed representation of an object is text which describes that object.  */)
  (Lisp_Object object, Lisp_Object noescape)
{
  Lisp_Object printcharfun;
  /* struct gcpro gcpro1, gcpro2; */
  Lisp_Object save_deactivate_mark;
  int count = SPECPDL_INDEX ();
  struct buffer *previous;

  specbind (Qinhibit_modification_hooks, Qt);

  {
    PRINTDECLARE;

    /* Save and restore this--we are altering a buffer
       but we don't want to deactivate the mark just for that.
       No need for specbind, since errors deactivate the mark.  */
    save_deactivate_mark = Vdeactivate_mark;
    /* GCPRO2 (object, save_deactivate_mark); */
    abort_on_gc++;

    printcharfun = Vprin1_to_string_buffer;
    PRINTPREPARE;
    print (object, printcharfun, NILP (noescape));
    /* Make Vprin1_to_string_buffer be the default buffer after PRINTFINSH */
    PRINTFINISH;
  }

  previous = current_buffer;
  set_buffer_internal (XBUFFER (Vprin1_to_string_buffer));
  object = Fbuffer_string ();
  if (SBYTES (object) == SCHARS (object))
    STRING_SET_UNIBYTE (object);

  /* Note that this won't make prepare_to_modify_buffer call
     ask-user-about-supersession-threat because this buffer
     does not visit a file.  */
  Ferase_buffer ();
  set_buffer_internal (previous);

  Vdeactivate_mark = save_deactivate_mark;
  /* UNGCPRO; */

  abort_on_gc--;
  return unbind_to (count, object);
}

DEFUN ("princ", Fprinc, Sprinc, 1, 2, 0,
       doc: /* Output the printed representation of OBJECT, any Lisp object.
No quoting characters are used; no delimiters are printed around
the contents of strings.

OBJECT is any of the Lisp data types: a number, a string, a symbol,
a list, a buffer, a window, a frame, etc.

A printed representation of an object is text which describes that object.

Optional argument PRINTCHARFUN is the output stream, which can be one
of these:

   - a buffer, in which case output is inserted into that buffer at point;
   - a marker, in which case output is inserted at marker's position;
   - a function, in which case that function is called once for each
     character of OBJECT's printed representation;
   - a symbol, in which case that symbol's function definition is called; or
   - t, in which case the output is displayed in the echo area.

If PRINTCHARFUN is omitted, the value of `standard-output' (which see)
is used instead.  */)
  (Lisp_Object object, Lisp_Object printcharfun)
{
  PRINTDECLARE;

  if (NILP (printcharfun))
    printcharfun = Vstandard_output;
  PRINTPREPARE;
  print (object, printcharfun, 0);
  PRINTFINISH;
  return object;
}

DEFUN ("print", Fprint, Sprint, 1, 2, 0,
       doc: /* Output the printed representation of OBJECT, with newlines around it.
Quoting characters are printed when needed to make output that `read'
can handle, whenever this is possible.  For complex objects, the behavior
is controlled by `print-level' and `print-length', which see.

OBJECT is any of the Lisp data types: a number, a string, a symbol,
a list, a buffer, a window, a frame, etc.

A printed representation of an object is text which describes that object.

Optional argument PRINTCHARFUN is the output stream, which can be one
of these:

   - a buffer, in which case output is inserted into that buffer at point;
   - a marker, in which case output is inserted at marker's position;
   - a function, in which case that function is called once for each
     character of OBJECT's printed representation;
   - a symbol, in which case that symbol's function definition is called; or
   - t, in which case the output is displayed in the echo area.

If PRINTCHARFUN is omitted, the value of `standard-output' (which see)
is used instead.  */)
  (Lisp_Object object, Lisp_Object printcharfun)
{
  PRINTDECLARE;
  struct gcpro gcpro1;

  if (NILP (printcharfun))
    printcharfun = Vstandard_output;
  GCPRO1 (object);
  PRINTPREPARE;
  PRINTCHAR ('\n');
  print (object, printcharfun, 1);
  PRINTCHAR ('\n');
  PRINTFINISH;
  UNGCPRO;
  return object;
}

/* The subroutine object for external-debugging-output is kept here
   for the convenience of the debugger.  */
Lisp_Object Qexternal_debugging_output;

DEFUN ("external-debugging-output", Fexternal_debugging_output, Sexternal_debugging_output, 1, 1, 0,
       doc: /* Write CHARACTER to stderr.
You can call print while debugging emacs, and pass it this function
to make it write to the debugging output.  */)
  (Lisp_Object character)
{
  CHECK_NUMBER (character);
  putc ((int) XINT (character), stderr);

#ifdef WINDOWSNT
  /* Send the output to a debugger (nothing happens if there isn't one).  */
  if (print_output_debug_flag)
    {
      char buf[2] = {(char) XINT (character), '\0'};
      OutputDebugString (buf);
    }
#endif

  return character;
}

/* This function is never called.  Its purpose is to prevent
   print_output_debug_flag from being optimized away.  */

void
debug_output_compilation_hack (int x)
{
  print_output_debug_flag = x;
}

#if defined (GNU_LINUX)

/* This functionality is not vitally important in general, so we rely on
   non-portable ability to use stderr as lvalue.  */

#define WITH_REDIRECT_DEBUGGING_OUTPUT 1

FILE *initial_stderr_stream = NULL;

DEFUN ("redirect-debugging-output", Fredirect_debugging_output, Sredirect_debugging_output,
       1, 2,
       "FDebug output file: \nP",
       doc: /* Redirect debugging output (stderr stream) to file FILE.
If FILE is nil, reset target to the initial stderr stream.
Optional arg APPEND non-nil (interactively, with prefix arg) means
append to existing target file.  */)
  (Lisp_Object file, Lisp_Object append)
{
  if (initial_stderr_stream != NULL)