>From 3739f4b6821435c9feb74b098e95f668d604c768 Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Mon, 1 Jul 2019 09:46:11 -0700
Subject: [PATCH 1/4] New function errprintf for printf to stderr
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This doesn’t change behavior; it just simplifies callers a bit
and makes further changes easier.
* src/alloc.c (mark_memory, test_setjmp, die):
* src/bidi.c (bidi_dump_cached_states):
* src/buffer.c (mmap_free_1, mmap_enlarge, mmap_alloc)
(init_buffer):
* src/charset.c (init_charset):
* src/dispextern.h (TRACE):
* src/dispnew.c (Fdump_redisplay_history)
(init_display_interactive):
* src/emacs-module.c (module_abort):
* src/emacs.c (main, sort_args, Fdump_emacs):
* src/gmalloc.c (mabort):
* src/gtkutil.c (my_log_handler, xg_set_geometry)
(xg_create_widget):
* src/image.c (convert_mono_to_color_image):
* src/lread.c (dir_warning):
* src/nsfont.m (ns_descriptor_to_entity, ns_findfonts)
(nsfont_list_family, nsfont_open, ns_uni_to_glyphs)
(ns_glyph_metrics, ns_dump_glyphstring):
* src/nsmenu.m (ns_update_menubar):
* src/nsterm.h (NSTRACE_MSG_NO_DASHES):
* src/nsterm.m (ns_mouse_position, ns_default, ns_term_init)
(sendEvent:, keyDown:, performDragOperation:, mouseDown:):
* src/pdumper.c (dump_trace, dump_fingerprint)
(print_paths_to_root_1, Fdump_emacs_portable):
* src/print.c (debug_print, safe_debug_print):
* src/regex-emacs.c (DEBUG_PRINT, debug_putchar)
(print_fastmap, print_partial_compiled_pattern)
(print_compiled_pattern, print_double_string, regex_compile):
* src/region-cache.c (pp_cache):
* src/systhread.c (sys_mutex_init, sys_cond_init):
* src/term.c (vfatal):
* src/unexaix.c (CHECK_SCNHDR):
* src/unexelf.c (DEBUG_LOG, unexec):
* src/unexhp9k800.c (read_header):
* src/unexmacosx.c (unexec_error):
* src/widget.c (EmacsFrameInitialize):
* src/xdisp.c (TRACE_MOVE, pos_visible_p, message_to_stderr)
(vmessage, debug_method_add, dump_glyph, dump_glyph_row)
(Fdump_glyph_matrix, dump_glyph_string, expose_window)
(expose_frame):
* src/xfaces.c (Fdump_colors, dump_realized_face)
(Fdump_face, Fshow_face_resources):
* src/xfns.c (print_fontset_result):
* src/xmenu.c (x_menu_show) [XDEBUG]:
* src/xrdb.c (fatal):
* src/xselect.c (TRACE0, TRACE1, TRACE2, TRACE3)
(x_clipboard_manager_error_2):
* src/xsmfns.c (x_session_initialize):
* src/xterm.c (x_trace_wire, x_connection_closed)
(my_log_handler, x_initialize):
Prefer the new functions to using fprintf etc. to stderr.
All files changed to include sysstdio.h instead if stdio.h
if they weren’t doing so already.
* src/dispextern.h (TRACE):
* src/xdisp.c (TRACE_MOVE):
All callers changed to omit stderr, since macro now arranges
for stderr itself.
* src/sysdep.c (errputc, errputs, errprintf, verrprintf):
New functions.
---
 src/alloc.c        |  12 +-
 src/bidi.c         |  24 ++--
 src/buffer.c       |  16 +--
 src/charset.c      |   2 +-
 src/dispnew.c      |  13 +-
 src/emacs-module.c |   8 +-
 src/emacs.c        |  57 ++++----
 src/gmalloc.c      |   2 +-
 src/gtkutil.c      |   9 +-
 src/image.c        |   2 +-
 src/lread.c        |   2 +-
 src/nsfont.m       |  41 +++---
 src/nsmenu.m       |  12 +-
 src/nsterm.h       |  11 +-
 src/nsterm.m       |  27 ++--
 src/pdumper.c      |  34 +++--
 src/print.c        |   8 +-
 src/regex-emacs.c  | 134 +++++++++----------
 src/region-cache.c |  15 +--
 src/sysdep.c       |  29 ++++
 src/sysstdio.h     |   5 +
 src/systhread.c    |   7 +-
 src/term.c         |   6 +-
 src/unexaix.c      |   7 +-
 src/unexelf.c      |   8 +-
 src/unexhp9k800.c  |   2 +-
 src/unexmacosx.c   |   6 +-
 src/widget.c       |   3 +-
 src/xdisp.c        | 324 ++++++++++++++++++++++-----------------------
 src/xfaces.c       |  64 ++++-----
 src/xfns.c         |   6 +-
 src/xmenu.c        |   2 +-
 src/xrdb.c         |   2 +-
 src/xselect.c      |  12 +-
 src/xsmfns.c       |   6 +-
 src/xterm.c        |  15 +--
 36 files changed, 473 insertions(+), 460 deletions(-)

diff --git a/src/alloc.c b/src/alloc.c
index 64aaa8acdf..9610f01c05 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -22,7 +22,6 @@ Copyright (C) 1985-1986, 1988, 1993-1995, 1997-2019 Free Software
 
 #include <errno.h>
 #include <stdint.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <limits.h>		/* For CHAR_BIT.  */
 #include <signal.h>		/* For SIGABRT, SIGDANGER.  */
@@ -38,6 +37,7 @@ Copyright (C) 1985-1986, 1988, 1993-1995, 1997-2019 Free Software
 #include "ptr-bounds.h"
 #include "puresize.h"
 #include "sheap.h"
+#include "sysstdio.h"
 #include "systime.h"
 #include "character.h"
 #include "buffer.h"
@@ -4717,7 +4717,7 @@ mark_memory (void const *start, void const *end)
        Lisp_Object obj = build_string ("test");
        struct Lisp_String *s = XSTRING (obj);
        garbage_collect ();
-       fprintf (stderr, "test '%s'\n", s->u.s.data);
+       errprintf ("test '%s'\n", s->u.s.data);
        return Qnil;
      }
 
@@ -4813,10 +4813,10 @@ test_setjmp (void)
          taking place, or the setjmp just didn't save the register.  */
 
       if (x == 1)
-	fprintf (stderr, SETJMP_WILL_LIKELY_WORK);
+	errputs (SETJMP_WILL_LIKELY_WORK);
       else
 	{
-	  fprintf (stderr, SETJMP_WILL_NOT_WORK);
+	  errputs (SETJMP_WILL_NOT_WORK);
 	  exit (1);
 	}
     }
@@ -7189,8 +7189,8 @@ DEFUN ("suspicious-object", Fsuspicious_object, Ssuspicious_object, 1, 1, 0,
 void
 die (const char *msg, const char *file, int line)
 {
-  fprintf (stderr, "\r\n%s:%d: Emacs fatal error: assertion failed: %s\r\n",
-	   file, line, msg);
+  errprintf ("\r\n%s:%d: Emacs fatal error: assertion failed: %s\r\n",
+	     file, line, msg);
   terminate_due_to_signal (SIGABRT, INT_MAX);
 }
 
diff --git a/src/bidi.c b/src/bidi.c
index c530d49c10..991894c4e0 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -238,13 +238,13 @@ Copyright (C) 2000-2001, 2004-2005, 2009-2019 Free Software Foundation, Inc.
    necessary.  */
 
 #include <config.h>
-#include <stdio.h>
 
 #include "lisp.h"
 #include "character.h"
 #include "buffer.h"
 #include "dispextern.h"
 #include "region-cache.h"
+#include "sysstdio.h"
 
 static bool bidi_initialized = 0;
 
@@ -3586,24 +3586,22 @@ bidi_dump_cached_states (void)
 
   if (bidi_cache_idx == 0)
     {
-      fprintf (stderr, "The cache is empty.\n");
+      errputs ("The cache is empty.\n");
       return;
     }
-  fprintf (stderr, "Total of  %"pD"d state%s in cache:\n",
-	   bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s");
+  errprintf ("Total of  %"pD"d state%s in cache:\n",
+	     bidi_cache_idx, bidi_cache_idx == 1 ? "" : "s");
 
   for (i = bidi_cache[bidi_cache_idx - 1].charpos; i > 0; i /= 10)
     ndigits++;
-  fputs ("ch  ", stderr);
+  errputs ("ch  ");
   for (i = 0; i < bidi_cache_idx; i++)
-    fprintf (stderr, "%*c", ndigits, bidi_cache[i].ch);
-  fputs ("\n", stderr);
-  fputs ("lvl ", stderr);
+    errprintf ("%*c", ndigits, bidi_cache[i].ch);
+  errputs ("\nlvl ");
   for (i = 0; i < bidi_cache_idx; i++)
-    fprintf (stderr, "%*d", ndigits, bidi_cache[i].resolved_level);
-  fputs ("\n", stderr);
-  fputs ("pos ", stderr);
+    errprintf ("%*d", ndigits, bidi_cache[i].resolved_level);
+  errputs ("\npos ");
   for (i = 0; i < bidi_cache_idx; i++)
-    fprintf (stderr, "%*"pD"d", ndigits, bidi_cache[i].charpos);
-  fputs ("\n", stderr);
+    errprintf ("%*"pD"d", ndigits, bidi_cache[i].charpos);
+  errputc ('\n');
 }
diff --git a/src/buffer.c b/src/buffer.c
index 209e29f0f1..14477d4ae1 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -24,7 +24,6 @@ Copyright (C) 1985-1989, 1993-1995, 1997-2019 Free Software Foundation,
 #include <sys/stat.h>
 #include <sys/param.h>
 #include <errno.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -33,6 +32,7 @@ Copyright (C) 1985-1989, 1993-1995, 1997-2019 Free Software Foundation,
 #include "lisp.h"
 #include "intervals.h"
 #include "process.h"
+#include "sysstdio.h"
 #include "systime.h"
 #include "window.h"
 #include "commands.h"
@@ -4781,7 +4781,7 @@ mmap_free_1 (struct mmap_region *r)
     mmap_regions = r->next;
 
   if (munmap (r, r->nbytes_mapped) == -1)
-    fprintf (stderr, "munmap: %s\n", emacs_strerror (errno));
+    errprintf ("munmap: %s\n", emacs_strerror (errno));
 }
 
 
@@ -4800,7 +4800,7 @@ mmap_enlarge (struct mmap_region *r, int npages)
       /* Unmap pages at the end of the region.  */
       nbytes = - npages * mmap_page_size;
       if (munmap (region_end - nbytes, nbytes) == -1)
-	fprintf (stderr, "munmap: %s\n", emacs_strerror (errno));
+	errprintf ("munmap: %s\n", emacs_strerror (errno));
       else
 	{
 	  r->nbytes_mapped -= nbytes;
@@ -4822,14 +4822,14 @@ mmap_enlarge (struct mmap_region *r, int npages)
 	  p = mmap (region_end, nbytes, PROT_READ | PROT_WRITE,
 		    MAP_ANON | MAP_PRIVATE | MAP_FIXED, mmap_fd, 0);
 	  if (p == MAP_FAILED)
-	    ; /* fprintf (stderr, "mmap: %s\n", emacs_strerror (errno)); */
+	    ; /* errprintf ("mmap: %s\n", emacs_strerror (errno)); */
 	  else if (p != region_end)
 	    {
 	      /* Kernels are free to choose a different address.  In
 		 that case, unmap what we've mapped above; we have
 		 no use for it.  */
 	      if (munmap (p, nbytes) == -1)
-		fprintf (stderr, "munmap: %s\n", emacs_strerror (errno));
+		errprintf ("munmap: %s\n", emacs_strerror (errno));
 	    }
 	  else
 	    {
@@ -4867,7 +4867,7 @@ mmap_alloc (void **var, size_t nbytes)
   if (p == MAP_FAILED)
     {
       if (errno != ENOMEM)
-	fprintf (stderr, "mmap: %s\n", emacs_strerror (errno));
+	errprintf ("mmap: %s\n", emacs_strerror (errno));
       p = NULL;
     }
   else
@@ -5378,8 +5378,8 @@ init_buffer (void)
 
   if (!pwd)
     {
-      fprintf (stderr, "Error getting directory: %s\n",
-               emacs_strerror (errno));
+      errprintf ("Error getting directory: %s\n",
+		 emacs_strerror (errno));
       bset_directory (current_buffer, Qnil);
     }
   else
diff --git a/src/charset.c b/src/charset.c
index c0700f972e..f2efc7946a 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -2293,7 +2293,7 @@ init_charset (void)
       /* This used to be non-fatal (dir_warning), but it should not
          happen, and if it does sooner or later it will cause some
          obscure problem (eg bug#6401), so better abort.  */
-      fprintf (stderr, "Error: charsets directory not found:\n\
+      errprintf ("Error: charsets directory not found:\n\
 %s\n\
 Emacs will not function correctly without the character map files.\n%s\
 Please check your installation!\n",
diff --git a/src/dispnew.c b/src/dispnew.c
index 52a7b6d6ee..28f0c49c0b 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -220,7 +220,7 @@ DEFUN ("dump-redisplay-history", Fdump_redisplay_history,
     {
       if (i < 0)
 	i = REDISPLAY_HISTORY_SIZE - 1;
-      fprintf (stderr, "%s\n", redisplay_history[i].trace);
+      errprintf ("%s\n", redisplay_history[i].trace);
     }
 
   return Qnil;
@@ -6153,8 +6153,7 @@ init_display_interactive (void)
 
       if (display_arg && !x_display_ok (display))
 	{
-	  fprintf (stderr, "Display %s unavailable, simulating -nw\n",
-		   display);
+	  errprintf ("Display %s unavailable, simulating -nw\n", display);
 	  inhibit_window_system = 1;
 	}
     }
@@ -6204,12 +6203,14 @@ init_display_interactive (void)
 #endif
   if (!terminal_type)
     {
+      char const *msg = ("Please set the environment variable "
+			 "TERM; see 'tset'.");
 #ifdef HAVE_WINDOW_SYSTEM
       if (! inhibit_window_system)
-	fprintf (stderr, "Please set the environment variable DISPLAY or TERM (see 'tset').\n");
-      else
+	msg = ("Please set the environment variable "
+	       "DISPLAY or TERM (see 'tset').");
 #endif /* HAVE_WINDOW_SYSTEM */
-	fprintf (stderr, "Please set the environment variable TERM; see 'tset'.\n");
+      errprintf ("%s\n", msg);
       exit (1);
     }
 
diff --git a/src/emacs-module.c b/src/emacs-module.c
index c856663d2f..7faad14adc 100644
--- a/src/emacs-module.c
+++ b/src/emacs-module.c
@@ -81,7 +81,6 @@ #define EMACS_MODULE_GMP
 #include <stdarg.h>
 #include <stddef.h>
 #include <stdint.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
 
@@ -91,6 +90,7 @@ #define EMACS_MODULE_GMP
 #include "coding.h"
 #include "keyboard.h"
 #include "syssignal.h"
+#include "sysstdio.h"
 #include "thread.h"
 
 #include <intprops.h>
@@ -1299,12 +1299,12 @@ value_storage_contains_p (const struct emacs_value_storage *storage,
 static AVOID ATTRIBUTE_FORMAT_PRINTF (1, 2)
 module_abort (const char *format, ...)
 {
-  fputs ("Emacs module assertion: ", stderr);
+  errputs ("Emacs module assertion: ");
   va_list args;
   va_start (args, format);
-  vfprintf (stderr, format, args);
+  verrprintf (format, args);
   va_end (args);
-  fputc ('\n', stderr);
+  errputc ('\n');
   fflush (NULL);
   emacs_abort ();
 }
diff --git a/src/emacs.c b/src/emacs.c
index 32bb57e272..4fd45497fc 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -1145,12 +1145,12 @@ main (int argc, char **argv)
 	  tem2 = Fsymbol_value (intern_c_string ("emacs-copyright"));
 	  if (!STRINGP (tem))
 	    {
-	      fprintf (stderr, "Invalid value of 'emacs-version'\n");
+	      errputs ("Invalid value of 'emacs-version'\n");
 	      exit (1);
 	    }
 	  if (!STRINGP (tem2))
 	    {
-	      fprintf (stderr, "Invalid value of 'emacs-copyright'\n");
+	      errputs ("Invalid value of 'emacs-copyright'\n");
 	      exit (1);
 	    }
 	  else
@@ -1192,8 +1192,8 @@ main (int argc, char **argv)
 #endif
       if (chdir (ch_to_dir) != 0)
         {
-          fprintf (stderr, "%s: Can't chdir to %s: %s\n",
-                   argv[0], ch_to_dir, strerror (errno));
+          errprintf ("%s: Can't chdir to %s: %s\n",
+		     argv[0], ch_to_dir, strerror (errno));
           exit (1);
         }
       original_pwd = emacs_wd;
@@ -1317,15 +1317,15 @@ main (int argc, char **argv)
 		  != STDOUT_FILENO))
 	    {
 	      char *errstring = strerror (errno);
-	      fprintf (stderr, "%s: %s: %s\n", argv[0], term, errstring);
+	      errprintf ("%s: %s: %s\n", argv[0], term, errstring);
 	      exit (EXIT_FAILURE);
 	    }
 	  if (! isatty (STDIN_FILENO))
 	    {
-	      fprintf (stderr, "%s: %s: not a tty\n", argv[0], term);
+	      errprintf ("%s: %s: not a tty\n", argv[0], term);
 	      exit (EXIT_FAILURE);
 	    }
-	  fprintf (stderr, "Using %s\n", term);
+	  errprintf ("Using %s\n", term);
 #ifdef HAVE_WINDOW_SYSTEM
 	  inhibit_window_system = true; /* -t => -nw */
 #endif
@@ -1422,7 +1422,7 @@ main (int argc, char **argv)
              before exiting.  */
           if (emacs_pipe (daemon_pipe) != 0)
             {
-              fprintf (stderr, "Cannot pipe!\n");
+              errputs ("Cannot pipe!\n");
               exit (1);
             }
         } /* daemon_type == 2 */
@@ -1432,8 +1432,7 @@ main (int argc, char **argv)
       int systemd_socket = sd_listen_fds (1);
 
       if (systemd_socket > 1)
-        fprintf (stderr,
-		 ("\n"
+	errputs (("\n"
 		  "Warning: systemd passed more than one socket to Emacs.\n"
 		  "Try 'Accept=false' in the Emacs socket unit file.\n"));
       else if (systemd_socket == 1
@@ -1443,7 +1442,7 @@ main (int argc, char **argv)
 #endif /* HAVE_LIBSYSTEMD */
 
 #ifdef USE_GTK
-      fprintf (stderr, "\nWarning: due to a long standing Gtk+ bug\nhttps://gitlab.gnome.org/GNOME/gtk/issues/221\n\
+      errputs ("\nWarning: due to a long standing Gtk+ bug\nhttps://gitlab.gnome.org/GNOME/gtk/issues/221\n\
 Emacs might crash when run in daemon mode and the X11 connection is unexpectedly lost.\n\
 Using an Emacs configured with --with-x-toolkit=lucid does not have this problem.\n");
 #endif /* USE_GTK */
@@ -1477,12 +1476,12 @@ main (int argc, char **argv)
 
               if (retval < 0)
                 {
-                  fprintf (stderr, "Error reading status from child\n");
+                  errputs ("Error reading status from child\n");
                   exit (1);
                 }
               else if (retval == 0)
                 {
-                  fprintf (stderr, "Error: server did not start correctly\n");
+                  errputs ("Error: server did not start correctly\n");
                   exit (1);
                 }
 
@@ -1508,7 +1507,7 @@ main (int argc, char **argv)
 
                 if (! (0 <= fdStrlen && fdStrlen < sizeof fdStr))
                   {
-                    fprintf (stderr, "daemon: child name too long\n");
+                    errputs ("daemon: child name too long\n");
                     exit (EXIT_CANNOT_INVOKE);
                   }
 
@@ -1525,7 +1524,7 @@ main (int argc, char **argv)
             if (!dname_arg || !*dname_arg || strnlen (dname_arg, 71) == 71
 		|| !strchr (dname_arg, '\n'))
           {
-            fprintf (stderr, "emacs daemon: daemon name absent or too long\n");
+            errputs ("emacs daemon: daemon name absent or too long\n");
             exit (EXIT_CANNOT_INVOKE);
           }
             dname_arg2[0] = '\0';
@@ -1546,12 +1545,12 @@ main (int argc, char **argv)
       w32_daemon_event = CreateEvent (NULL, TRUE, FALSE, W32_DAEMON_EVENT);
       if (w32_daemon_event == NULL)
         {
-          fprintf (stderr, "Couldn't create MS-Windows event for daemon: %s\n",
-		   w32_strerror (0));
+          errprintf ("Couldn't create MS-Windows event for daemon: %s\n",
+		     w32_strerror (0));
           exit (1);
         }
 #else /* MSDOS */
-      fprintf (stderr, "This platform does not support daemon mode.\n");
+      errputs ("This platform does not support daemon mode.\n");
       exit (1);
 #endif /* MSDOS */
       if (dname_arg)
@@ -1662,7 +1661,7 @@ main (int argc, char **argv)
                 NULL, &skip_args);
   if (will_dump_p () && module_assertions)
     {
-      fputs ("Module assertions are not supported during dumping\n", stderr);
+      errputs ("Module assertions are not supported during dumping\n");
       exit (1);
     }
   init_module_assertions (module_assertions);
@@ -2329,7 +2328,9 @@ sort_args (int argc, char **argv)
 		{
 		  /* This is an internal error.
 		     Eg if one long option is a prefix of another.  */
-		  fprintf (stderr, "Option '%s' matched multiple standard arguments\n", argv[from]);
+		  errprintf
+		    ("Option '%s' matched multiple standard arguments\n",
+		     argv[from]);
 		}
 	      /* Should we not also warn if there was no match?	 */
 	    }
@@ -2566,14 +2567,14 @@ DEFUN ("dump-emacs", Fdump_emacs, Sdump_emacs, 2, 2, 0,
 
   if (heap_bss_diff > MAX_HEAP_BSS_DIFF)
     {
-      fprintf (stderr, "**************************************************\n");
-      fprintf (stderr, "Warning: Your system has a gap between BSS and the\n");
-      fprintf (stderr, "heap (%"pMu" bytes).  This usually means that exec-shield\n",
-               heap_bss_diff);
-      fprintf (stderr, "or something similar is in effect.  The dump may\n");
-      fprintf (stderr, "fail because of this.  See the section about\n");
-      fprintf (stderr, "exec-shield in etc/PROBLEMS for more information.\n");
-      fprintf (stderr, "**************************************************\n");
+      errprintf (("**************************************************\n"
+		  "Warning: Your system has a gap between BSS and the\n"
+		  "heap (%"pMu" bytes).  This usually means that exec-shield\n"
+		  "or something similar is in effect.  The dump may\n"
+		  "fail because of this.  See the section about\n"
+		  "exec-shield in etc/PROBLEMS for more information.\n"
+		  "**************************************************\n"),
+		 heap_bss_diff);
     }
 # endif
 
diff --git a/src/gmalloc.c b/src/gmalloc.c
index bac3ffb7e5..57ebe12d3c 100644
--- a/src/gmalloc.c
+++ b/src/gmalloc.c
@@ -2012,7 +2012,7 @@ mabort (enum mcheck_status status)
 #ifdef __GNU_LIBRARY__
   __libc_fatal (msg);
 #else
-  fprintf (stderr, "mcheck: %s\n", msg);
+  errprintf ("mcheck: %s\n", msg);
   emacs_abort ();
 #endif
 }
diff --git a/src/gtkutil.c b/src/gtkutil.c
index 1d15aec253..3c8447a0c4 100644
--- a/src/gtkutil.c
+++ b/src/gtkutil.c
@@ -21,13 +21,13 @@ Copyright (C) 2003-2019 Free Software Foundation, Inc.
 
 #ifdef USE_GTK
 #include <float.h>
-#include <stdio.h>
 
 #include <c-ctype.h>
 
 #include "lisp.h"
 #include "dispextern.h"
 #include "frame.h"
+#include "sysstdio.h"
 #include "systime.h"
 #include "xterm.h"
 #include "blockinput.h"
@@ -829,7 +829,7 @@ my_log_handler (const gchar *log_domain, GLogLevelFlags log_level,
 		const gchar *msg, gpointer user_data)
 {
   if (!strstr (msg, "visible children"))
-    fprintf (stderr, "XX %s-WARNING **: %s\n", log_domain, msg);
+    errprintf ("XX %s-WARNING **: %s\n", log_domain, msg);
 }
 #endif
 
@@ -894,7 +894,7 @@ xg_set_geometry (struct frame *f)
 
 	  if (!gtk_window_parse_geometry (GTK_WINDOW (FRAME_GTK_OUTER_WIDGET (f)),
 					  geom_str))
-	    fprintf (stderr, "Failed to parse: '%s'\n", geom_str);
+	    errprintf ("Failed to parse: '%s'\n", geom_str);
 
 	  g_log_remove_handler ("Gtk", id);
 	}
@@ -2850,8 +2850,7 @@ xg_create_widget (const char *type, const char *name, struct frame *f,
     }
   else
     {
-      fprintf (stderr, "bad type in xg_create_widget: %s, doing nothing\n",
-               type);
+      errprintf ("bad type in xg_create_widget: %s, doing nothing\n", type);
     }
 
   return w;
diff --git a/src/image.c b/src/image.c
index d44a9d3dc2..864f73f8ef 100644
--- a/src/image.c
+++ b/src/image.c
@@ -3335,7 +3335,7 @@ convert_mono_to_color_image (struct frame *f, struct image *img,
   DeleteDC (new_img_dc);
   DeleteObject (img->pixmap);
   if (new_pixmap == 0)
-    fprintf (stderr, "Failed to convert image to color.\n");
+    errputs ("Failed to convert image to color.\n");
   else
     img->pixmap = new_pixmap;
 }
diff --git a/src/lread.c b/src/lread.c
index 5fa90cad3f..da8dd774dc 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -4721,7 +4721,7 @@ dir_warning (char const *use, Lisp_Object dirname)
 {
   static char const format[] = "Warning: %s '%s': %s\n";
   char *diagnostic = emacs_strerror (errno);
-  fprintf (stderr, format, use, SSDATA (ENCODE_SYSTEM (dirname)), diagnostic);
+  errprintf (format, use, SSDATA (ENCODE_SYSTEM (dirname)), diagnostic);
 
   /* Don't log the warning before we've initialized!!  */
   if (initialized)
diff --git a/src/nsfont.m b/src/nsfont.m
index eca97ab86c..0bda357e3a 100644
--- a/src/nsfont.m
+++ b/src/nsfont.m
@@ -212,7 +212,7 @@ static void ns_glyph_metrics (struct nsfont_info *font_info,
 
     if (NSFONT_TRACE)
       {
-	fprintf (stderr, "created font_entity:\n    ");
+	errputs ("created font_entity:\n    ");
 	debug_print (font_entity);
       }
 
@@ -313,7 +313,7 @@ static void ns_glyph_metrics (struct nsfont_info *font_info,
 	    if (*bytes1 == 0)  // *bytes1 & *bytes2 != *bytes2
 		off++;
 	  }
-    // fprintf(stderr, "off = %d\ttot = %d\n", off,tot);
+    // errprintf ("off = %d\ttot = %d\n", off,tot);
     return (float)off / tot < 1.0F - pct;
 }
 
@@ -542,8 +542,8 @@ but also for ascii (which causes unnecessary font substitution).  */
     block_input ();
     if (NSFONT_TRACE)
       {
-	fprintf (stderr, "nsfont: %s for fontspec:\n    ",
-		 (isMatch ? "match" : "list"));
+	errprintf ("nsfont: %s for fontspec:\n    ",
+		   (isMatch ? "match" : "list"));
 	debug_print (font_spec);
       }
 
@@ -596,8 +596,8 @@ but also for ascii (which causes unnecessary font substitution).  */
       return ns_fallback_entity ();
 
     if (NSFONT_TRACE)
-	fprintf (stderr, "    Returning %"pD"d entities.\n",
-		 list_length (list));
+	errprintf ("    Returning %"pD"d entities.\n",
+		   list_length (list));
 
     return list;
 }
@@ -668,8 +668,8 @@ Properties to be considered are same as for list().  */
   /* FIXME: escape the name?  */
 
   if (NSFONT_TRACE)
-    fprintf (stderr, "nsfont: list families returning %"pD"d entries\n",
-	     list_length (list));
+    errprintf ("nsfont: list families returning %"pD"d entries\n",
+	       list_length (list));
 
   unblock_input ();
   return list;
@@ -698,7 +698,7 @@ Properties to be considered are same as for list().  */
 
   if (NSFONT_TRACE)
     {
-      fprintf (stderr, "nsfont: open size %d of fontentity:\n    ", pixel_size);
+      errprintf ("nsfont: open size %d of fontentity:\n    ", pixel_size);
       debug_print (font_entity);
     }
 
@@ -1272,8 +1272,8 @@ is false when (FROM > 0 || TO < S->nchars).  */
   unsigned short *glyphs;
 
   if (NSFONT_TRACE)
-    fprintf (stderr, "%p\tFinding glyphs for glyphs in block %d\n",
-            font_info, block);
+    errprintf ("%p\tFinding glyphs for glyphs in block %d\n",
+	       font_info, block);
 
   block_input ();
 
@@ -1348,8 +1348,8 @@ is false when (FROM > 0 || TO < S->nchars).  */
   struct font_metrics *metrics;
 
   if (NSFONT_TRACE)
-    fprintf (stderr, "%p\tComputing metrics for glyphs in block %d\n",
-            font_info, block);
+    errprintf ("%p\tComputing metrics for glyphs in block %d\n",
+	       font_info, block);
 
 #ifdef NS_IMPL_GNUSTEP
   /* not implemented yet (as of startup 0.18), so punt */
@@ -1472,16 +1472,13 @@ - (void)setIntAttribute: (NSInteger)attributeTag value: (NSInteger)val
 {
   int i;
 
-  fprintf (stderr, "Glyph string len = %d at (%d, %d) overhang (%d, %d),"
-"overlap = %d, bg_filled = %d:",
-           s->nchars, s->x, s->y, s->left_overhang, s->right_overhang,
-           s->row->overlapping_p, s->background_filled_p);
+  errprintf (("Glyph string len = %d at (%d, %d) overhang (%d, %d),"
+	      "overlap = %d, bg_filled = %d:"),
+	     s->nchars, s->x, s->y, s->left_overhang, s->right_overhang,
+	     s->row->overlapping_p, s->background_filled_p);
   for (i =0; i<s->nchars; i++)
-    {
-      int c = s->first_glyph[i].u.ch;
-      fprintf (stderr, "%c", c);
-    }
-  fprintf (stderr, "\n");
+    errputc (s->first_glyph[i].u.ch);
+  errputc ('\n');
 }
 
 static void syms_of_nsfont_for_pdumper (void);
diff --git a/src/nsmenu.m b/src/nsmenu.m
index 817f8cff18..099f20bb0d 100644
--- a/src/nsmenu.m
+++ b/src/nsmenu.m
@@ -119,7 +119,7 @@
   if (f != SELECTED_FRAME ())
       return;
   XSETFRAME (Vmenu_updating_frame, f);
-/*fprintf (stderr, "ns_update_menubar: frame: %p\tdeep: %d\tsub: %p\n", f, deep_p, submenu); */
+/*errprintf ("ns_update_menubar: frame: %p\tdeep: %d\tsub: %p\n", f, deep_p, submenu); */
 
   block_input ();
   pool = [[NSAutoreleasePool alloc] init];
@@ -236,8 +236,8 @@
       if (submenu && n == 0)
         {
           /* should have found a menu for this one but didn't */
-          fprintf (stderr, "ERROR: did not find lisp menu for submenu '%s'.\n",
-                  [[submenu title] UTF8String]);
+          errprintf ("ERROR: did not find lisp menu for submenu '%s'.\n",
+		     [[submenu title] UTF8String]);
 	  discard_menu_items ();
 	  unbind_to (specpdl_count, Qnil);
           [pool release];
@@ -292,7 +292,7 @@
 #if NSMENUPROFILE
               ftime (&tb);
               t += 1000*tb.time+tb.millitm;
-              fprintf (stderr, "NO CHANGE!  CUTTING OUT after %ld msec.\n", t);
+              errprintf ("NO CHANGE!  CUTTING OUT after %ld msec.\n", t);
 #endif
 
               free_menubar_widget_value_tree (first_wv);
@@ -447,7 +447,7 @@
 #if NSMENUPROFILE
   ftime (&tb);
   t += 1000*tb.time+tb.millitm;
-  fprintf (stderr, "Menu update took %ld msec.\n", t);
+  errprintf ("Menu update took %ld msec.\n", t);
 #endif
 
   /* set main menu */
@@ -581,7 +581,7 @@ - (void)menuNeedsUpdate: (NSMenu *)menu
   */
   if (trackingMenu == 0)
     return;
-/*fprintf (stderr, "Updating menu '%s'\n", [[self title] UTF8String]); NSLog (@"%@\n", event); */
+/*errprintf ("Updating menu '%s'\n", [[self title] UTF8String]); NSLog (@"%@\n", event); */
 #ifdef NS_IMPL_GNUSTEP
   /* Don't know how to do this for anything other than Mac OS X 10.5 and later.
      This is wrong, as it might run Lisp code in the event loop.  */
diff --git a/src/nsterm.h b/src/nsterm.h
index 567f462ec6..7e15b9cd34 100644
--- a/src/nsterm.h
+++ b/src/nsterm.h
@@ -23,6 +23,7 @@
 #include "character.h"
 #include "font.h"
 #include "sysselect.h"
+#include "sysstdio.h"
 
 #ifdef HAVE_NS
 #ifdef __OBJC__
@@ -176,11 +177,11 @@ #define NSTRACE_MSG_NO_DASHES(...)                                          \
     {                                                                       \
       if (nstrace_enabled)                                                  \
         {                                                                   \
-          fprintf (stderr, "%-10s:%5d: [%5d]%.*s",                          \
-                   __FILE__, __LINE__, nstrace_num++,                       \
-                   2*nstrace_depth, "  | | | | | | | | | | | | | | | ..");  \
-          fprintf (stderr, __VA_ARGS__);                                    \
-          fprintf (stderr, "\n");                                           \
+	  errprintf ("%-10s:%5d: [%5d]%.*s",				    \
+		     __FILE__, __LINE__, nstrace_num++,			    \
+		     2*nstrace_depth, "  | | | | | | | | | | | | | | | .."); \
+	  errprintf (__VA_ARGS__);					    \
+	  errputc ('\n');						    \
         }                                                                   \
     }                                                                       \
   while(0)
diff --git a/src/nsterm.m b/src/nsterm.m
index bc1c7860aa..91eab1b0d2 100644
--- a/src/nsterm.m
+++ b/src/nsterm.m
@@ -2121,7 +2121,7 @@ so some key presses (TAB) are swallowed by the system.  */
 
   color_table->colors[idx] = color;
   [color retain];
-  /* fprintf(stderr, "color_table: allocated %d\n",idx); */
+  /* errprintf ("color_table: allocated %d\n", idx); */
   return idx;
 }
 
@@ -2466,7 +2466,7 @@ so some key presses (TAB) are swallowed by the system.  */
 
   if (*fp == NULL)
     {
-      fprintf (stderr, "Warning: ns_mouse_position () called with null *fp.\n");
+      errputs ("Warning: ns_mouse_position () called with null *fp.\n");
       return;
     }
 
@@ -5032,8 +5032,8 @@ static Lisp_Object ns_string_to_lispmod (const char *s)
         *result = make_float (f);
       else if (is_modstring && value)
         *result = ns_string_to_lispmod (value);
-      else fprintf (stderr,
-                   "Bad value for default \"%s\": \"%s\"\n", parameter, value);
+      else
+	errprintf ("Bad value for default \"%s\": \"%s\"\n", parameter, value);
     }
 }
 
@@ -5222,8 +5222,7 @@ static Lisp_Object ns_new_font (struct frame *f, Lisp_Object font_object,
     {
       if (emacs_pipe (selfds) != 0)
         {
-          fprintf (stderr, "Failed to create pipe: %s\n",
-                   emacs_strerror (errno));
+          errprintf ("Failed to create pipe: %s\n", emacs_strerror (errno));
           emacs_abort ();
         }
 
@@ -5613,7 +5612,7 @@ - (void)sendEvent: (NSEvent *)theEvent
 
   if (type == NSEventTypeCursorUpdate && window == nil)
     {
-      fprintf (stderr, "Dropping external cursor update event.\n");
+      errputs ("Dropping external cursor update event.\n");
       return;
     }
 
@@ -6288,8 +6287,8 @@ In that case we use UCKeyTranslate (ns_get_shifted_character)
         emacs_event->modifiers ^= parse_solitary_modifier (ns_function_modifier);
 
       if (NS_KEYLOG)
-        fprintf (stderr, "keyDown: code =%x\tfnKey =%x\tflags = %x\tmods = %x\n",
-                 code, fnKeysym, flags, emacs_event->modifiers);
+        errprintf ("keyDown: code =%x\tfnKey =%x\tflags = %x\tmods = %x\n",
+		   code, fnKeysym, flags, emacs_event->modifiers);
 
       /* If it was a function key or had control-like modifiers, pass
          it directly to Emacs.  */
@@ -6333,7 +6332,7 @@ In that case we use UCKeyTranslate (ns_get_shifted_character)
      https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/EventOverview/HandlingKeyEvents/HandlingKeyEvents.html.  */
 
   if (NS_KEYLOG && !processingCompose)
-    fprintf (stderr, "keyDown: Begin compose sequence.\n");
+    errputs ("keyDown: Begin compose sequence.\n");
 
   /* FIXME: interpretKeyEvents doesn’t seem to send insertText if ⌘ is
      used as shift-like modifier, at least on El Capitan.  Mask it
@@ -8291,7 +8290,7 @@ -(BOOL)performDragOperation: (id <NSDraggingInfo>) sender
     }
   else
     {
-      fprintf (stderr, "Invalid data type in dragging pasteboard\n");
+      errputs ("Invalid data type in dragging pasteboard\n");
       return NO;
     }
 
@@ -9035,8 +9034,8 @@ - (void)mouseDown: (NSEvent *)e
     case NSScrollerKnobSlot:  /* GNUstep-only */
       last_hit_part = scroll_bar_move_ratio; break;
     default:  /* NSScrollerNoPart? */
-      fprintf (stderr, "EmacsScroller-mouseDown: unexpected part %ld\n",
-               (long) part);
+      errprintf ("EmacsScroller-mouseDown: unexpected part %ld\n",
+		 (long) part);
       return;
     }
 
@@ -9319,7 +9318,7 @@ Convert an X font name (XLFD) to an NS font name.
             name[i+1] = c_toupper (name[i+1]);
         }
     }
-  /* fprintf (stderr, "converted '%s' to '%s'\n",xlfd,name); */
+  /* errprintf ("converted '%s' to '%s'\n", xlfd, name); */
   ret = [[NSString stringWithUTF8String: name] UTF8String];
   xfree (name);
   return ret;
diff --git a/src/pdumper.c b/src/pdumper.c
index c00f8a0af5..bfa0dba7f0 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -23,7 +23,6 @@
 #include <math.h>
 #include <stdarg.h>
 #include <stdint.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <sys/mman.h>
 #include <sys/param.h>
@@ -42,6 +41,7 @@
 #include "lisp.h"
 #include "pdumper.h"
 #include "window.h"
+#include "sysstdio.h"
 #include "systime.h"
 #include "thread.h"
 #include "bignum.h"
@@ -158,7 +158,7 @@ dump_trace (const char *fmt, ...)
     {
       va_list args;
       va_start (args, fmt);
-      vfprintf (stderr, fmt, args);
+      verrprintf (fmt, args);
       va_end (args);
     }
 }
@@ -326,10 +326,10 @@ dump_reloc_set_offset (struct dump_reloc *reloc, dump_off offset)
 static void
 dump_fingerprint (const char *label, unsigned char const *xfingerprint)
 {
-  fprintf (stderr, "%s: ", label);
+  errprintf ("%s: ", label);
   for (int i = 0; i < 32; ++i)
-    fprintf (stderr, "%02x", (unsigned) xfingerprint[i]);
-  fprintf (stderr, "\n");
+    errprintf ("%02x", (unsigned) xfingerprint[i]);
+  errputc ('\n');
 }
 
 /* Format of an Emacs portable dump file.  All offsets are relative to
@@ -1403,10 +1403,9 @@ print_paths_to_root_1 (struct dump_context *ctx,
       Lisp_Object referrer = XCAR (referrers);
       referrers = XCDR (referrers);
       Lisp_Object repr = Fprin1_to_string (referrer, Qnil);
-      for (int i = 0; i < level; ++i)
-        fputc (' ', stderr);
+      errprintf ("%*s", level, "");
       fwrite (SDATA (repr), 1, SBYTES (repr), stderr);
-      fputc ('\n', stderr);
+      errputc ('\n');
       print_paths_to_root_1 (ctx, referrer, level + 1);
     }
 }
@@ -4226,16 +4225,15 @@ DEFUN ("dump-emacs-portable",
   dump_seek (ctx, 0);
   dump_write (ctx, &ctx->header, sizeof (ctx->header));
 
-  fprintf (stderr, "Dump complete\n");
-  fprintf (stderr,
-           "Byte counts: header=%lu hot=%lu discardable=%lu cold=%lu\n",
-           (unsigned long) (header_end - header_start),
-           (unsigned long) (hot_end - hot_start),
-           (unsigned long) (discardable_end - ctx->header.discardable_start),
-           (unsigned long) (cold_end - ctx->header.cold_start));
-  fprintf (stderr, "Reloc counts: hot=%u discardable=%u\n",
-           number_hot_relocations,
-           number_discardable_relocations);
+  errputs ("Dump complete\n");
+  errprintf ("Byte counts: header=%lu hot=%lu discardable=%lu cold=%lu\n",
+	     (unsigned long) (header_end - header_start),
+	     (unsigned long) (hot_end - hot_start),
+	     (unsigned long) (discardable_end - ctx->header.discardable_start),
+	     (unsigned long) (cold_end - ctx->header.cold_start));
+  errprintf ("Reloc counts: hot=%u discardable=%u\n",
+	     number_hot_relocations,
+	     number_discardable_relocations);
 
   unblock_input ();
   return unbind_to (count, Qnil);
diff --git a/src/print.c b/src/print.c
index 406abbf4a3..df45cb27ce 100644
--- a/src/print.c
+++ b/src/print.c
@@ -840,7 +840,7 @@ DEFUN ("redirect-debugging-output", Fredirect_debugging_output, Sredirect_debugg
 debug_print (Lisp_Object arg)
 {
   Fprin1 (arg, Qexternal_debugging_output);
-  fprintf (stderr, "\r\n");
+  errputs ("\r\n");
 }
 
 void safe_debug_print (Lisp_Object) EXTERNALLY_VISIBLE;
@@ -854,9 +854,9 @@ safe_debug_print (Lisp_Object arg)
   else
     {
       EMACS_UINT n = XLI (arg);
-      fprintf (stderr, "#<%s_LISP_OBJECT 0x%08"pI"x>\r\n",
-	       !valid ? "INVALID" : "SOME",
-	       n);
+      errprintf ("#<%s_LISP_OBJECT 0x%08"pI"x>\r\n",
+		 !valid ? "INVALID" : "SOME",
+		 n);
     }
 }
 
diff --git a/src/regex-emacs.c b/src/regex-emacs.c
index ac9f91dacb..83850b8b7d 100644
--- a/src/regex-emacs.c
+++ b/src/regex-emacs.c
@@ -442,7 +442,7 @@ #define CHARSET_RANGE_TABLE_END(range_table, count)	\
 
 # define DEBUG_STATEMENT(e) e
 # define DEBUG_PRINT(...)                                       \
-  if (regex_emacs_debug > 0) fprintf (stderr, __VA_ARGS__)
+  if (regex_emacs_debug > 0) errprintf (__VA_ARGS__)
 # define DEBUG_COMPILES_ARGUMENTS
 # define DEBUG_PRINT_COMPILED_PATTERN(p, s, e)				\
   if (regex_emacs_debug > 0) print_partial_compiled_pattern (s, e)
@@ -453,11 +453,11 @@ #define CHARSET_RANGE_TABLE_END(range_table, count)	\
 debug_putchar (int c)
 {
   if (c >= 32 && c <= 126)
-    fputc (c, stderr);
+    errputc (c);
   else
     {
       unsigned int uc = c;
-      fprintf (stderr, "{%02x}", uc);
+      errprintf ("{%02x}", uc);
     }
 }
 
@@ -482,12 +482,12 @@ print_fastmap (char *fastmap)
 	    }
 	  if (was_a_range)
 	    {
-	      fprintf (stderr, "-");
+	      errputs ("-");
 	      debug_putchar (i - 1);
 	    }
 	}
     }
-  fputc ('\n', stderr);
+  errputc ('\n');
 }
 
 
@@ -503,50 +503,50 @@ print_partial_compiled_pattern (re_char *start, re_char *end)
 
   if (start == NULL)
     {
-      fprintf (stderr, "(null)\n");
+      errputs ("(null)\n");
       return;
     }
 
   /* Loop over pattern commands.  */
   while (p < pend)
     {
-      fprintf (stderr, "%td:\t", p - start);
+      errprintf ("%td:\t", p - start);
 
       switch ((re_opcode_t) *p++)
 	{
 	case no_op:
-	  fprintf (stderr, "/no_op");
+	  errputs ("/no_op");
 	  break;
 
 	case succeed:
-	  fprintf (stderr, "/succeed");
+	  errputs ("/succeed");
 	  break;
 
 	case exactn:
 	  mcnt = *p++;
-	  fprintf (stderr, "/exactn/%d", mcnt);
+	  errprintf ("/exactn/%d", mcnt);
 	  do
 	    {
-	      fprintf (stderr, "/");
+	      errputc ('/');
 	      debug_putchar (*p++);
 	    }
 	  while (--mcnt);
 	  break;
 
 	case start_memory:
-	  fprintf (stderr, "/start_memory/%d", *p++);
+	  errprintf ("/start_memory/%d", *p++);
 	  break;
 
 	case stop_memory:
-	  fprintf (stderr, "/stop_memory/%d", *p++);
+	  errprintf ("/stop_memory/%d", *p++);
 	  break;
 
 	case duplicate:
-	  fprintf (stderr, "/duplicate/%d", *p++);
+	  errprintf ("/duplicate/%d", *p++);
 	  break;
 
 	case anychar:
-	  fprintf (stderr, "/anychar");
+	  errputs ("/anychar");
 	  break;
 
 	case charset:
@@ -557,11 +557,11 @@ print_partial_compiled_pattern (re_char *start, re_char *end)
 	    int length = CHARSET_BITMAP_SIZE (p - 1);
 	    bool has_range_table = CHARSET_RANGE_TABLE_EXISTS_P (p - 1);
 
-	    fprintf (stderr, "/charset [%s",
-		     (re_opcode_t) *(p - 1) == charset_not ? "^" : "");
+	    errprintf ("/charset [%s",
+		       (re_opcode_t) *(p - 1) == charset_not ? "^" : "");
 
 	    if (p + *p >= pend)
-	      fprintf (stderr, " !extends past end of pattern! ");
+	      errputs (" !extends past end of pattern! ");
 
 	    for (c = 0; c < 256; c++)
 	      if (c / 8 < length
@@ -570,7 +570,7 @@ print_partial_compiled_pattern (re_char *start, re_char *end)
 		  /* Are we starting a range?  */
 		  if (last + 1 == c && ! in_range)
 		    {
-		      fprintf (stderr, "-");
+		      errputc ('-');
 		      in_range = true;
 		    }
 		  /* Have we broken a range?  */
@@ -589,14 +589,14 @@ print_partial_compiled_pattern (re_char *start, re_char *end)
 	    if (in_range)
 	      debug_putchar (last);
 
-	    fprintf (stderr, "]");
+	    errputc (']');
 
 	    p += 1 + length;
 
 	    if (has_range_table)
 	      {
 		int count;
-		fprintf (stderr, "has-range-table");
+		errputs ("has-range-table");
 
 		/* ??? Should print the range table; for now, just skip it.  */
 		p += 2;		/* skip range table bits */
@@ -607,136 +607,136 @@ print_partial_compiled_pattern (re_char *start, re_char *end)
 	  break;
 
 	case begline:
-	  fprintf (stderr, "/begline");
+	  errputs ("/begline");
 	  break;
 
 	case endline:
-	  fprintf (stderr, "/endline");
+	  errputs ("/endline");
 	  break;
 
 	case on_failure_jump:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
-	  fprintf (stderr, "/on_failure_jump to %td", p + mcnt - start);
+	  errprintf ("/on_failure_jump to %td", p + mcnt - start);
 	  break;
 
 	case on_failure_keep_string_jump:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
-	  fprintf (stderr, "/on_failure_keep_string_jump to %td",
-		   p + mcnt - start);
+	  errprintf ("/on_failure_keep_string_jump to %td",
+		     p + mcnt - start);
 	  break;
 
 	case on_failure_jump_nastyloop:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
-	  fprintf (stderr, "/on_failure_jump_nastyloop to %td",
-		   p + mcnt - start);
+	  errprintf ("/on_failure_jump_nastyloop to %td",
+		     p + mcnt - start);
 	  break;
 
 	case on_failure_jump_loop:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
-	  fprintf (stderr, "/on_failure_jump_loop to %td",
-		   p + mcnt - start);
+	  errprintf ("/on_failure_jump_loop to %td",
+		     p + mcnt - start);
 	  break;
 
 	case on_failure_jump_smart:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
-	  fprintf (stderr, "/on_failure_jump_smart to %td",
-		   p + mcnt - start);
+	  errprintf ("/on_failure_jump_smart to %td",
+		     p + mcnt - start);
 	  break;
 
 	case jump:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
-	  fprintf (stderr, "/jump to %td", p + mcnt - start);
+	  errprintf ("/jump to %td", p + mcnt - start);
 	  break;
 
 	case succeed_n:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
 	  EXTRACT_NUMBER_AND_INCR (mcnt2, p);
-	  fprintf (stderr, "/succeed_n to %td, %d times",
-		   p - 2 + mcnt - start, mcnt2);
+	  errprintf ("/succeed_n to %td, %d times",
+		     p - 2 + mcnt - start, mcnt2);
 	  break;
 
 	case jump_n:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
 	  EXTRACT_NUMBER_AND_INCR (mcnt2, p);
-	  fprintf (stderr, "/jump_n to %td, %d times",
-		   p - 2 + mcnt - start, mcnt2);
+	  errprintf ("/jump_n to %td, %d times",
+		     p - 2 + mcnt - start, mcnt2);
 	  break;
 
 	case set_number_at:
 	  EXTRACT_NUMBER_AND_INCR (mcnt, p);
 	  EXTRACT_NUMBER_AND_INCR (mcnt2, p);
-	  fprintf (stderr, "/set_number_at location %td to %d",
-		   p - 2 + mcnt - start, mcnt2);
+	  errprintf ("/set_number_at location %td to %d",
+		     p - 2 + mcnt - start, mcnt2);
 	  break;
 
 	case wordbound:
-	  fprintf (stderr, "/wordbound");
+	  errputs ("/wordbound");
 	  break;
 
 	case notwordbound:
-	  fprintf (stderr, "/notwordbound");
+	  errputs ("/notwordbound");
 	  break;
 
 	case wordbeg:
-	  fprintf (stderr, "/wordbeg");
+	  errputs ("/wordbeg");
 	  break;
 
 	case wordend:
-	  fprintf (stderr, "/wordend");
+	  errputs ("/wordend");
 	  break;
 
 	case symbeg:
-	  fprintf (stderr, "/symbeg");
+	  errputs ("/symbeg");
 	  break;
 
 	case symend:
-	  fprintf (stderr, "/symend");
+	  errputs ("/symend");
 	  break;
 
 	case syntaxspec:
-	  fprintf (stderr, "/syntaxspec");
+	  errputs ("/syntaxspec");
 	  mcnt = *p++;
-	  fprintf (stderr, "/%d", mcnt);
+	  errprintf ("/%d", mcnt);
 	  break;
 
 	case notsyntaxspec:
-	  fprintf (stderr, "/notsyntaxspec");
+	  errputs ("/notsyntaxspec");
 	  mcnt = *p++;
-	  fprintf (stderr, "/%d", mcnt);
+	  errprintf ("/%d", mcnt);
 	  break;
 
 	case at_dot:
-	  fprintf (stderr, "/at_dot");
+	  errputs ("/at_dot");
 	  break;
 
 	case categoryspec:
-	  fprintf (stderr, "/categoryspec");
+	  errputs ("/categoryspec");
 	  mcnt = *p++;
-	  fprintf (stderr, "/%d", mcnt);
+	  errprintf ("/%d", mcnt);
 	  break;
 
 	case notcategoryspec:
-	  fprintf (stderr, "/notcategoryspec");
+	  errputs ("/notcategoryspec");
 	  mcnt = *p++;
-	  fprintf (stderr, "/%d", mcnt);
+	  errprintf ("/%d", mcnt);
 	  break;
 
 	case begbuf:
-	  fprintf (stderr, "/begbuf");
+	  errputs ("/begbuf");
 	  break;
 
 	case endbuf:
-	  fprintf (stderr, "/endbuf");
+	  errputs ("/endbuf");
 	  break;
 
 	default:
-	  fprintf (stderr, "?%d", *(p-1));
+	  errprintf ("?%d", *(p-1));
 	}
 
-      fprintf (stderr, "\n");
+      errputc ('\n');
     }
 
-  fprintf (stderr, "%td:\tend of pattern.\n", p - start);
+  errprintf ("%td:\tend of pattern.\n", p - start);
 }
 
 
@@ -746,18 +746,18 @@ print_compiled_pattern (struct re_pattern_buffer *bufp)
   re_char *buffer = bufp->buffer;
 
   print_partial_compiled_pattern (buffer, buffer + bufp->used);
-  fprintf (stderr, "%td bytes used/%td bytes allocated.\n",
-           bufp->used, bufp->allocated);
+  errprintf ("%td bytes used/%td bytes allocated.\n",
+	     bufp->used, bufp->allocated);
 
   if (bufp->fastmap_accurate && bufp->fastmap)
     {
-      fprintf (stderr, "fastmap: ");
+      errputs ("fastmap: ");
       print_fastmap (bufp->fastmap);
     }
 
-  fprintf (stderr, "re_nsub: %td\t", bufp->re_nsub);
-  fprintf (stderr, "regs_alloc: %d\t", bufp->regs_allocated);
-  fprintf (stderr, "can_be_null: %d\n", bufp->can_be_null);
+  errprintf ("re_nsub: %td\t", bufp->re_nsub);
+  errprintf ("regs_alloc: %d\t", bufp->regs_allocated);
+  errprintf ("can_be_null: %d\n", bufp->can_be_null);
   fflush (stderr);
   /* Perhaps we should print the translate table?  */
 }
@@ -768,7 +768,7 @@ print_double_string (re_char *where, re_char *string1, ptrdiff_t size1,
 		     re_char *string2, ptrdiff_t size2)
 {
   if (where == NULL)
-    fprintf (stderr, "(null)");
+    errputs ("(null)");
   else
     {
       int i;
@@ -1751,7 +1751,7 @@ regex_compile (re_char *pattern, ptrdiff_t size,
     {
       for (ptrdiff_t debug_count = 0; debug_count < size; debug_count++)
 	debug_putchar (pattern[debug_count]);
-      fputc ('\n', stderr);
+      errputc ('\n');
     }
 #endif
 
diff --git a/src/region-cache.c b/src/region-cache.c
index 57a26f2fa6..51604e815f 100644
--- a/src/region-cache.c
+++ b/src/region-cache.c
@@ -762,19 +762,18 @@ pp_cache (struct region_cache *c)
   ptrdiff_t beg_u = c->buffer_beg + c->beg_unchanged;
   ptrdiff_t end_u = c->buffer_end - c->end_unchanged;
 
-  fprintf (stderr,
-           "basis: %"pD"d..%"pD"d    modified: %"pD"d..%"pD"d\n",
-           c->buffer_beg, c->buffer_end,
-           beg_u, end_u);
+  errprintf ("basis: %"pD"d..%"pD"d    modified: %"pD"d..%"pD"d\n",
+	     c->buffer_beg, c->buffer_end,
+	     beg_u, end_u);
 
   for (ptrdiff_t i = 0; i < c->cache_len; i++)
     {
       ptrdiff_t pos = BOUNDARY_POS (c, i);
 
-      fprintf (stderr, "%c%c%"pD"d : %d\n",
-	       pos < beg_u ? 'v' : pos == beg_u ? '-' : ' ',
-	       pos > end_u ? '^' : pos == end_u ? '-' : ' ',
-	       pos, BOUNDARY_VALUE (c, i));
+      errprintf ("%c%c%"pD"d : %d\n",
+		 pos < beg_u ? 'v' : pos == beg_u ? '-' : ' ',
+		 pos > end_u ? '^' : pos == end_u ? '-' : ' ',
+		 pos, BOUNDARY_VALUE (c, i));
     }
 }
 
diff --git a/src/sysdep.c b/src/sysdep.c
index 4f89e8aba1..beccc3c537 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -2767,6 +2767,35 @@ safe_strsignal (int code)
 
   return signame;
 }
+
+/* Output to stderr.  */
+
+void
+errputc (int c)
+{
+  fputc_unlocked (c, stderr);
+}
+
+void
+errputs (char const *str)
+{
+  fputs_unlocked (str, stderr);
+}
+
+void
+errprintf (char const *fmt, ...)
+{
+  va_list ap;
+  va_start (ap, fmt);
+  verrprintf (fmt, ap);
+  va_end (ap);
+}
+
+void
+verrprintf (char const *fmt, va_list ap)
+{
+  vfprintf (stderr, fmt, ap);
+}
 
 #ifndef DOS_NT
 /* For make-serial-process  */
diff --git a/src/sysstdio.h b/src/sysstdio.h
index 3ff1d6a572..ebe0845d40 100644
--- a/src/sysstdio.h
+++ b/src/sysstdio.h
@@ -25,6 +25,11 @@ #define EMACS_SYSSTDIO_H
 
 extern FILE *emacs_fopen (char const *, char const *);
 
+extern void errputc (int);
+extern void errputs (char const *);
+extern void errprintf (char const *, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
+extern void verrprintf (char const *, va_list) ATTRIBUTE_FORMAT_PRINTF (1, 0);
+
 #if O_BINARY
 # define FOPEN_BINARY "b"
 # define FOPEN_TEXT "t"
diff --git a/src/systhread.c b/src/systhread.c
index 6f4de536fb..ef57c0e8b3 100644
--- a/src/systhread.c
+++ b/src/systhread.c
@@ -18,9 +18,10 @@ Copyright (C) 2012-2019 Free Software Foundation, Inc.
 
 #include <config.h>
 #include <setjmp.h>
-#include <stdio.h>
 #include <string.h>
+
 #include "lisp.h"
+#include "sysstdio.h"
 
 #ifdef HAVE_NS
 #include "nsterm.h"
@@ -122,7 +123,7 @@ sys_mutex_init (sys_mutex_t *mutex)
   /* We could get ENOMEM.  Can't do anything except aborting.  */
   if (error != 0)
     {
-      fprintf (stderr, "\npthread_mutex_init failed: %s\n", strerror (error));
+      errprintf ("\npthread_mutex_init failed: %s\n", strerror (error));
       emacs_abort ();
     }
 #ifdef ENABLE_CHECKING
@@ -152,7 +153,7 @@ sys_cond_init (sys_cond_t *cond)
   /* We could get ENOMEM.  Can't do anything except aborting.  */
   if (error != 0)
     {
-      fprintf (stderr, "\npthread_cond_init failed: %s\n", strerror (error));
+      errprintf ("\npthread_cond_init failed: %s\n", strerror (error));
       emacs_abort ();
     }
 }
diff --git a/src/term.c b/src/term.c
index 8b5a710d80..5b9c010520 100644
--- a/src/term.c
+++ b/src/term.c
@@ -4398,10 +4398,10 @@ init_tty (const char *name, const char *terminal_type, bool must_succeed)
 static void
 vfatal (const char *str, va_list ap)
 {
-  fprintf (stderr, "emacs: ");
-  vfprintf (stderr, str, ap);
+  errputs ("emacs: ");
+  verrprintf (str, ap);
   if (! (str[0] && str[strlen (str) - 1] == '\n'))
-    fprintf (stderr, "\n");
+    errputc ('\n');
   exit (1);
 }
 
diff --git a/src/unexaix.c b/src/unexaix.c
index 349d365383..a273ba1adb 100644
--- a/src/unexaix.c
+++ b/src/unexaix.c
@@ -225,12 +225,11 @@ make_hdr (int new, int a_out,
 #define CHECK_SCNHDR(ptr, name, flags) \
   if (strcmp (s->s_name, name) == 0) { \
     if (s->s_flags != flags) { \
-      fprintf (stderr, "unexec: %lx flags where %x expected in %s section.\n", \
-               (unsigned long)s->s_flags, flags, name);                 \
+      errprintf ("unexec: %lx flags where %x expected in %s section.\n", \
+		 (unsigned long) s->s_flags, flags, name);		\
     } \
     if (ptr) { \
-      fprintf (stderr, "unexec: duplicate section header for section %s.\n", \
-               name);                                                   \
+      errprintf ("unexec: duplicate section header for section %s.\n", name); \
     } \
     ptr = s; \
   }
diff --git a/src/unexelf.c b/src/unexelf.c
index 6d19bf1fb9..d09a5f5aac 100644
--- a/src/unexelf.c
+++ b/src/unexelf.c
@@ -187,7 +187,7 @@ verify ((! TYPE_SIGNED (ElfW (Half))
 	&& TYPE_MAXIMUM (ElfW (Half)) <= PTRDIFF_MAX);
 
 #ifdef UNEXELF_DEBUG
-# define DEBUG_LOG(expr) fprintf (stderr, #expr " 0x%jx\n", (uintmax_t) (expr))
+# define DEBUG_LOG(expr) errprintf (#expr " 0x%jx\n", (uintmax_t) (expr))
 #endif
 
 /* Get the address of a particular section or program header entry,
@@ -344,7 +344,7 @@ unexec (const char *new_name, const char *old_name)
   new_data2_offset = old_bss_offset;
 
 #ifdef UNEXELF_DEBUG
-  fprintf (stderr, "old_bss_index %td\n", old_bss_index);
+  errprintf ("old_bss_index %td\n", old_bss_index);
   DEBUG_LOG (old_bss_addr);
   DEBUG_LOG (old_bss_size);
   DEBUG_LOG (old_bss_offset);
@@ -395,9 +395,9 @@ unexec (const char *new_name, const char *old_name)
 
 #ifdef UNEXELF_DEBUG
   DEBUG_LOG (old_file_h->e_shoff);
-  fprintf (stderr, "Old section count %td\n", (ptrdiff_t) old_file_h->e_shnum);
+  errprintf ("Old section count %td\n", (ptrdiff_t) old_file_h->e_shnum);
   DEBUG_LOG (new_file_h->e_shoff);
-  fprintf (stderr, "New section count %td\n", (ptrdiff_t) new_file_h->e_shnum);
+  errprintf ("New section count %td\n", (ptrdiff_t) new_file_h->e_shnum);
 #endif
 
   /* Fix up program header.  Extend the writable data segment so
diff --git a/src/unexhp9k800.c b/src/unexhp9k800.c
index cbf1835b9e..48d516fa2f 100644
--- a/src/unexhp9k800.c
+++ b/src/unexhp9k800.c
@@ -167,7 +167,7 @@ read_header (int file, struct header *hdr, struct som_exec_auxhdr *auxhdr)
   if (hdr->a_magic != EXEC_MAGIC && hdr->a_magic != SHARE_MAGIC
       &&  hdr->a_magic != DEMAND_MAGIC)
     {
-      fprintf (stderr, "a.out file doesn't have valid magic number\n");
+      errputs ("a.out file doesn't have valid magic number\n");
       exit (1);
     }
 
diff --git a/src/unexmacosx.c b/src/unexmacosx.c
index a94c0cccb6..4c93301369 100644
--- a/src/unexmacosx.c
+++ b/src/unexmacosx.c
@@ -303,9 +303,9 @@ unexec_error (const char *format, ...)
   va_list ap;
 
   va_start (ap, format);
-  fprintf (stderr, "unexec: ");
-  vfprintf (stderr, format, ap);
-  fprintf (stderr, "\n");
+  errputs ("unexec: ");
+  verrprintf (format, ap);
+  errputc ('\n');
   va_end (ap);
   exit (1);
 }
diff --git a/src/widget.c b/src/widget.c
index e662dd3ecd..a150088c93 100644
--- a/src/widget.c
+++ b/src/widget.c
@@ -364,8 +364,7 @@ EmacsFrameInitialize (Widget request, Widget new, ArgList dum1, Cardinal *dum2)
 
   if (!ew->emacs_frame.frame)
     {
-      fprintf (stderr,
-	       "can't create an emacs frame widget without a frame\n");
+      errputs ("can't create an emacs frame widget without a frame\n");
       exit (1);
     }
 
diff --git a/src/xdisp.c b/src/xdisp.c
index c13a950e3a..4dbb183bd5 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -302,7 +302,6 @@ Copyright (C) 1985-1988, 1993-1995, 1997-2019 Free Software Foundation,
    buffer_posn_from_coords in dispnew.c for how this is handled.  */
 
 #include <config.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <limits.h>
 #include <math.h>
@@ -311,6 +310,7 @@ Copyright (C) 1985-1988, 1993-1995, 1997-2019 Free Software Foundation,
 #include "atimer.h"
 #include "composite.h"
 #include "keyboard.h"
+#include "sysstdio.h"
 #include "systime.h"
 #include "frame.h"
 #include "window.h"
@@ -1762,10 +1762,10 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int *x, int *y,
 #if false
   /* Debugging code.  */
   if (visible_p)
-    fprintf (stderr, "+pv pt=%d vs=%d --> x=%d y=%d rt=%d rb=%d rh=%d vp=%d\n",
-	     charpos, w->vscroll, *x, *y, *rtop, *rbot, *rowh, *vpos);
+    errprintf ("+pv pt=%d vs=%d --> x=%d y=%d rt=%d rb=%d rh=%d vp=%d\n",
+	       charpos, w->vscroll, *x, *y, *rtop, *rbot, *rowh, *vpos);
   else
-    fprintf (stderr, "-pv pt=%d vs=%d\n", charpos, w->vscroll);
+    errprintf ("-pv pt=%d vs=%d\n", charpos, w->vscroll);
 #endif
 
   /* Restore potentially overwritten values.  */
@@ -10713,7 +10713,7 @@ message_to_stderr (Lisp_Object m)
   if (noninteractive_need_newline)
     {
       noninteractive_need_newline = false;
-      fputc ('\n', stderr);
+      errputc ('\n');
     }
   if (STRINGP (m))
     {
@@ -10741,7 +10741,7 @@ message_to_stderr (Lisp_Object m)
       }
     }
   else if (!cursor_in_echo_area)
-    fputc ('\n', stderr);
+    errputc ('\n');
 
   fflush (stderr);
 }
@@ -10888,11 +10888,11 @@ vmessage (const char *m, va_list ap)
       if (m)
 	{
 	  if (noninteractive_need_newline)
-	    fputc ('\n', stderr);
+	    errputc ('\n');
 	  noninteractive_need_newline = false;
-	  vfprintf (stderr, m, ap);
+	  verrprintf (m, ap);
 	  if (!cursor_in_echo_area)
-	    fputc ('\n', stderr);
+	    errputc ('\n');
 	  fflush (stderr);
 	}
     }
@@ -13679,13 +13679,13 @@ debug_method_add (struct window *w, char const *fmt, ...)
   va_end (ap);
 
   if (trace_redisplay_p)
-    fprintf (stderr, "%p (%s): %s\n",
-	     ptr,
-	     ((BUFFERP (w->contents)
-	       && STRINGP (BVAR (XBUFFER (w->contents), name)))
-	      ? SSDATA (BVAR (XBUFFER (w->contents), name))
-	      : "no buffer"),
-	     method + len);
+    errprintf ("%p (%s): %s\n",
+	       ptr,
+	       ((BUFFERP (w->contents)
+		 && STRINGP (BVAR (XBUFFER (w->contents), name)))
+		? SSDATA (BVAR (XBUFFER (w->contents), name))
+		: "no buffer"),
+	       method + len);
 }
 
 #endif /* GLYPH_DEBUG */
@@ -19521,117 +19521,111 @@ dump_glyph (struct glyph_row *row, struct glyph *glyph, int area)
   if (glyph->type == CHAR_GLYPH
       || glyph->type == GLYPHLESS_GLYPH)
     {
-      fprintf (stderr,
-	       "  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x      %c %4d %1.1d%1.1d\n",
-	       glyph - row->glyphs[TEXT_AREA],
-	       (glyph->type == CHAR_GLYPH
-		? 'C'
-		: 'G'),
-	       glyph->charpos,
-	       (BUFFERP (glyph->object)
-		? 'B'
-		: (STRINGP (glyph->object)
-		   ? 'S'
-		   : (NILP (glyph->object)
-		      ? '0'
-		      : '-'))),
-	       glyph->pixel_width,
-	       glyph->u.ch,
-	       (glyph->u.ch < 0x80 && glyph->u.ch >= ' '
-		? (int) glyph->u.ch
-		: '.'),
-	       glyph->face_id,
-	       glyph->left_box_line_p,
-	       glyph->right_box_line_p);
+      errprintf ("  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x      %c %4d %1.1d%1.1d\n",
+		 glyph - row->glyphs[TEXT_AREA],
+		 (glyph->type == CHAR_GLYPH
+		  ? 'C'
+		  : 'G'),
+		 glyph->charpos,
+		 (BUFFERP (glyph->object)
+		  ? 'B'
+		  : (STRINGP (glyph->object)
+		     ? 'S'
+		     : (NILP (glyph->object)
+			? '0'
+			: '-'))),
+		 glyph->pixel_width,
+		 glyph->u.ch,
+		 (glyph->u.ch < 0x80 && glyph->u.ch >= ' '
+		  ? (int) glyph->u.ch
+		  : '.'),
+		 glyph->face_id,
+		 glyph->left_box_line_p,
+		 glyph->right_box_line_p);
     }
   else if (glyph->type == STRETCH_GLYPH)
     {
-      fprintf (stderr,
-	       "  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x      %c %4d %1.1d%1.1d\n",
-	       glyph - row->glyphs[TEXT_AREA],
-	       'S',
-	       glyph->charpos,
-	       (BUFFERP (glyph->object)
-		? 'B'
-		: (STRINGP (glyph->object)
-		   ? 'S'
-		   : (NILP (glyph->object)
-		      ? '0'
-		      : '-'))),
-	       glyph->pixel_width,
-	       0u,
-	       ' ',
-	       glyph->face_id,
-	       glyph->left_box_line_p,
-	       glyph->right_box_line_p);
+      errprintf ("  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x      %c %4d %1.1d%1.1d\n",
+		 glyph - row->glyphs[TEXT_AREA],
+		 'S',
+		 glyph->charpos,
+		 (BUFFERP (glyph->object)
+		  ? 'B'
+		  : (STRINGP (glyph->object)
+		     ? 'S'
+		     : (NILP (glyph->object)
+			? '0'
+			: '-'))),
+		 glyph->pixel_width,
+		 0u,
+		 ' ',
+		 glyph->face_id,
+		 glyph->left_box_line_p,
+		 glyph->right_box_line_p);
     }
   else if (glyph->type == IMAGE_GLYPH)
     {
-      fprintf (stderr,
-	       "  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x      %c %4d %1.1d%1.1d\n",
-	       glyph - row->glyphs[TEXT_AREA],
-	       'I',
-	       glyph->charpos,
-	       (BUFFERP (glyph->object)
-		? 'B'
-		: (STRINGP (glyph->object)
-		   ? 'S'
-		   : (NILP (glyph->object)
-		      ? '0'
-		      : '-'))),
-	       glyph->pixel_width,
-	       (unsigned int) glyph->u.img_id,
-	       '.',
-	       glyph->face_id,
-	       glyph->left_box_line_p,
-	       glyph->right_box_line_p);
+      errprintf ("  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x      %c %4d %1.1d%1.1d\n",
+		 glyph - row->glyphs[TEXT_AREA],
+		 'I',
+		 glyph->charpos,
+		 (BUFFERP (glyph->object)
+		  ? 'B'
+		  : (STRINGP (glyph->object)
+		     ? 'S'
+		     : (NILP (glyph->object)
+			? '0'
+			: '-'))),
+		 glyph->pixel_width,
+		 (unsigned int) glyph->u.img_id,
+		 '.',
+		 glyph->face_id,
+		 glyph->left_box_line_p,
+		 glyph->right_box_line_p);
     }
   else if (glyph->type == COMPOSITE_GLYPH)
     {
-      fprintf (stderr,
-	       "  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x",
-	       glyph - row->glyphs[TEXT_AREA],
-	       '+',
-	       glyph->charpos,
-	       (BUFFERP (glyph->object)
-		? 'B'
-		: (STRINGP (glyph->object)
-		   ? 'S'
-		   : (NILP (glyph->object)
-		      ? '0'
-		      : '-'))),
-	       glyph->pixel_width,
-	       (unsigned int) glyph->u.cmp.id);
+      errprintf ("  %5"pD"d     %c %9"pD"d   %c %3d 0x%06x",
+		 glyph - row->glyphs[TEXT_AREA],
+		 '+',
+		 glyph->charpos,
+		 (BUFFERP (glyph->object)
+		  ? 'B'
+		  : (STRINGP (glyph->object)
+		     ? 'S'
+		     : (NILP (glyph->object)
+			? '0'
+			: '-'))),
+		 glyph->pixel_width,
+		 (unsigned int) glyph->u.cmp.id);
       if (glyph->u.cmp.automatic)
-	fprintf (stderr,
-		 "[%d-%d]",
-		 glyph->slice.cmp.from, glyph->slice.cmp.to);
-      fprintf (stderr, " . %4d %1.1d%1.1d\n",
-	       glyph->face_id,
-	       glyph->left_box_line_p,
-	       glyph->right_box_line_p);
+	errprintf ("[%d-%d]",
+		   glyph->slice.cmp.from, glyph->slice.cmp.to);
+      errprintf (" . %4d %1.1d%1.1d\n",
+		 glyph->face_id,
+		 glyph->left_box_line_p,
+		 glyph->right_box_line_p);
     }
   else if (glyph->type == XWIDGET_GLYPH)
     {
 #ifndef HAVE_XWIDGETS
       eassume (false);
 #else
-      fprintf (stderr,
-	       "  %5td %4c %6td %c %3d %7p %c %4d %1.1d%1.1d\n",
-	       glyph - row->glyphs[TEXT_AREA],
-	       'X',
-	       glyph->charpos,
-	       (BUFFERP (glyph->object)
-		? 'B'
-		: (STRINGP (glyph->object)
-		   ? 'S'
-		   : '-')),
-	       glyph->pixel_width,
-	       glyph->u.xwidget,
-	       '.',
-	       glyph->face_id,
-	       glyph->left_box_line_p,
-	       glyph->right_box_line_p);
+      errprintf ("  %5td %4c %6td %c %3d %7p %c %4d %1.1d%1.1d\n",
+		 glyph - row->glyphs[TEXT_AREA],
+		 'X',
+		 glyph->charpos,
+		 (BUFFERP (glyph->object)
+		  ? 'B'
+		  : (STRINGP (glyph->object)
+		     ? 'S'
+		     : '-')),
+		 glyph->pixel_width,
+		 glyph->u.xwidget,
+		 '.',
+		 glyph->face_id,
+		 glyph->left_box_line_p,
+		 glyph->right_box_line_p);
 #endif
     }
 }
@@ -19647,43 +19641,43 @@ dump_glyph_row (struct glyph_row *row, int vpos, int glyphs)
 {
   if (glyphs != 1)
     {
-      fprintf (stderr, "Row     Start       End Used oE><\\CTZFesm     X    Y    W    H    V    A    P\n");
-      fprintf (stderr, "==============================================================================\n");
+      errputs ("Row     Start       End Used oE><\\CTZFesm     X    Y    W    H    V    A    P\n");
+      errputs ("==============================================================================\n");
 
-      fprintf (stderr, "%3d %9"pD"d %9"pD"d %4d %1.1d%1.1d%1.1d%1.1d\
+      errprintf ("%3d %9"pD"d %9"pD"d %4d %1.1d%1.1d%1.1d%1.1d\
 %1.1d%1.1d%1.1d%1.1d%1.1d%1.1d%1.1d%1.1d  %4d %4d %4d %4d %4d %4d %4d\n",
-	       vpos,
-	       MATRIX_ROW_START_CHARPOS (row),
-	       MATRIX_ROW_END_CHARPOS (row),
-	       row->used[TEXT_AREA],
-	       row->contains_overlapping_glyphs_p,
-	       row->enabled_p,
-	       row->truncated_on_left_p,
-	       row->truncated_on_right_p,
-	       row->continued_p,
-	       MATRIX_ROW_CONTINUATION_LINE_P (row),
-	       MATRIX_ROW_DISPLAYS_TEXT_P (row),
-	       row->ends_at_zv_p,
-	       row->fill_line_p,
-	       row->ends_in_middle_of_char_p,
-	       row->starts_in_middle_of_char_p,
-	       row->mouse_face_p,
-	       row->x,
-	       row->y,
-	       row->pixel_width,
-	       row->height,
-	       row->visible_height,
-	       row->ascent,
-	       row->phys_ascent);
+		 vpos,
+		 MATRIX_ROW_START_CHARPOS (row),
+		 MATRIX_ROW_END_CHARPOS (row),
+		 row->used[TEXT_AREA],
+		 row->contains_overlapping_glyphs_p,
+		 row->enabled_p,
+		 row->truncated_on_left_p,
+		 row->truncated_on_right_p,
+		 row->continued_p,
+		 MATRIX_ROW_CONTINUATION_LINE_P (row),
+		 MATRIX_ROW_DISPLAYS_TEXT_P (row),
+		 row->ends_at_zv_p,
+		 row->fill_line_p,
+		 row->ends_in_middle_of_char_p,
+		 row->starts_in_middle_of_char_p,
+		 row->mouse_face_p,
+		 row->x,
+		 row->y,
+		 row->pixel_width,
+		 row->height,
+		 row->visible_height,
+		 row->ascent,
+		 row->phys_ascent);
       /* The next 3 lines should align to "Start" in the header.  */
-      fprintf (stderr, "    %9"pD"d %9"pD"d\t%5d\n", row->start.overlay_string_index,
-	       row->end.overlay_string_index,
-	       row->continuation_lines_width);
-      fprintf (stderr, "    %9"pD"d %9"pD"d\n",
-	       CHARPOS (row->start.string_pos),
-	       CHARPOS (row->end.string_pos));
-      fprintf (stderr, "    %9d %9d\n", row->start.dpvec_index,
-	       row->end.dpvec_index);
+      errprintf ("    %9"pD"d %9"pD"d\t%5d\n", row->start.overlay_string_index,
+		 row->end.overlay_string_index,
+		 row->continuation_lines_width);
+      errprintf ("    %9"pD"d %9"pD"d\n",
+		 CHARPOS (row->start.string_pos),
+		 CHARPOS (row->end.string_pos));
+      errprintf ("    %9d %9d\n", row->start.dpvec_index,
+		 row->end.dpvec_index);
     }
 
   if (glyphs > 1)
@@ -19700,7 +19694,7 @@ dump_glyph_row (struct glyph_row *row, int vpos, int glyphs)
 	    ++glyph_end;
 
 	  if (glyph < glyph_end)
-	    fprintf (stderr, " Glyph#  Type       Pos   O   W     Code      C Face LR\n");
+	    errputs (" Glyph#  Type       Pos   O   W     Code      C Face LR\n");
 
 	  for (; glyph < glyph_end; ++glyph)
 	    dump_glyph (row, glyph, area);
@@ -19736,7 +19730,7 @@ dump_glyph_row (struct glyph_row *row, int vpos, int glyphs)
 	    }
 
 	  s[i] = '\0';
-	  fprintf (stderr, "%3d: (%d) '%s'\n", vpos, row->enabled_p, s);
+	  errprintf ("%3d: (%d) '%s'\n", vpos, row->enabled_p, s);
 	}
     }
 }
@@ -19756,11 +19750,11 @@ DEFUN ("dump-glyph-matrix", Fdump_glyph_matrix,
   struct window *w = XWINDOW (selected_window);
   struct buffer *buffer = XBUFFER (w->contents);
 
-  fprintf (stderr, "PT = %"pD"d, BEGV = %"pD"d. ZV = %"pD"d\n",
-	   BUF_PT (buffer), BUF_BEGV (buffer), BUF_ZV (buffer));
-  fprintf (stderr, "Cursor x = %d, y = %d, hpos = %d, vpos = %d\n",
-	   w->cursor.x, w->cursor.y, w->cursor.hpos, w->cursor.vpos);
-  fprintf (stderr, "=============================================\n");
+  errprintf ("PT = %"pD"d, BEGV = %"pD"d. ZV = %"pD"d\n",
+	     BUF_PT (buffer), BUF_BEGV (buffer), BUF_ZV (buffer));
+  errprintf ("Cursor x = %d, y = %d, hpos = %d, vpos = %d\n",
+	     w->cursor.x, w->cursor.y, w->cursor.hpos, w->cursor.vpos);
+  errputs ("=============================================\n");
   dump_glyph_matrix (w->current_matrix,
 		     TYPE_RANGED_FIXNUMP (int, glyphs) ? XFIXNUM (glyphs) : 0);
   return Qnil;
@@ -19777,7 +19771,7 @@ DEFUN ("dump-frame-glyph-matrix", Fdump_frame_glyph_matrix,
   if (f->current_matrix)
     dump_glyph_matrix (f->current_matrix, 1);
   else
-    fprintf (stderr, "*** This frame doesn't have a frame glyph matrix ***\n");
+    errputs ("*** This frame doesn't have a frame glyph matrix ***\n");
   return Qnil;
 }
 
@@ -25973,18 +25967,18 @@ get_font_ascent_descent (struct font *font, int *ascent, int *descent)
 void
 dump_glyph_string (struct glyph_string *s)
 {
-  fprintf (stderr, "glyph string\n");
-  fprintf (stderr, "  x, y, w, h = %d, %d, %d, %d\n",
-	   s->x, s->y, s->width, s->height);
-  fprintf (stderr, "  ybase = %d\n", s->ybase);
-  fprintf (stderr, "  hl = %u\n", s->hl);
-  fprintf (stderr, "  left overhang = %d, right = %d\n",
-	   s->left_overhang, s->right_overhang);
-  fprintf (stderr, "  nchars = %d\n", s->nchars);
-  fprintf (stderr, "  extends to end of line = %d\n",
-	   s->extends_to_end_of_line_p);
-  fprintf (stderr, "  font height = %d\n", FONT_HEIGHT (s->font));
-  fprintf (stderr, "  bg width = %d\n", s->background_width);
+  errputs ("glyph string\n");
+  errprintf ("  x, y, w, h = %d, %d, %d, %d\n",
+	     s->x, s->y, s->width, s->height);
+  errprintf ("  ybase = %d\n", s->ybase);
+  errprintf ("  hl = %u\n", s->hl);
+  errprintf ("  left overhang = %d, right = %d\n",
+	     s->left_overhang, s->right_overhang);
+  errprintf ("  nchars = %d\n", s->nchars);
+  errprintf ("  extends to end of line = %d\n",
+	     s->extends_to_end_of_line_p);
+  errprintf ("  font height = %d\n", FONT_HEIGHT (s->font));
+  errprintf ("  bg width = %d\n", s->background_width);
 }
 
 #endif /* GLYPH_DEBUG */
diff --git a/src/xfaces.c b/src/xfaces.c
index d9e66eaf2d..ed3bb0945e 100644
--- a/src/xfaces.c
+++ b/src/xfaces.c
@@ -418,21 +418,15 @@ DEFUN ("dump-colors", Fdump_colors, Sdump_colors, 0, 0, 0,
 {
   int i, n;
 
-  fputc ('\n', stderr);
+  errputc ('\n');
 
   for (i = n = 0; i < ARRAYELTS (color_count); ++i)
     if (color_count[i])
-      {
-	fprintf (stderr, "%3d: %5d", i, color_count[i]);
-	++n;
-	if (n % 5 == 0)
-	  fputc ('\n', stderr);
-	else
-	  fputc ('\t', stderr);
-      }
+      errprintf ("%3d: %5d%c", i, color_count[i],
+		 ++n % 5 == 0 ? '\n' : '\t');
 
   if (n % 5 != 0)
-    fputc ('\n', stderr);
+    errputc ('\n');
   return Qnil;
 }
 
@@ -6397,28 +6391,28 @@ DEFUN ("x-load-color-file", Fx_load_color_file,
 static void
 dump_realized_face (struct face *face)
 {
-  fprintf (stderr, "ID: %d\n", face->id);
+  errprintf ("ID: %d\n", face->id);
 #ifdef HAVE_X_WINDOWS
-  fprintf (stderr, "gc: %p\n", face->gc);
+  errprintf ("gc: %p\n", face->gc);
 #endif
-  fprintf (stderr, "foreground: 0x%lx (%s)\n",
-	   face->foreground,
-	   SDATA (face->lface[LFACE_FOREGROUND_INDEX]));
-  fprintf (stderr, "background: 0x%lx (%s)\n",
-	   face->background,
-	   SDATA (face->lface[LFACE_BACKGROUND_INDEX]));
+  errprintf ("foreground: 0x%lx (%s)\n",
+	     face->foreground,
+	     SDATA (face->lface[LFACE_FOREGROUND_INDEX]));
+  errprintf ("background: 0x%lx (%s)\n",
+	     face->background,
+	     SDATA (face->lface[LFACE_BACKGROUND_INDEX]));
   if (face->font)
-    fprintf (stderr, "font_name: %s (%s)\n",
-	     SDATA (face->font->props[FONT_NAME_INDEX]),
-	     SDATA (face->lface[LFACE_FAMILY_INDEX]));
+    errprintf ("font_name: %s (%s)\n",
+	       SDATA (face->font->props[FONT_NAME_INDEX]),
+	       SDATA (face->lface[LFACE_FAMILY_INDEX]));
 #ifdef HAVE_X_WINDOWS
-  fprintf (stderr, "font = %p\n", face->font);
+  errprintf ("font = %p\n", face->font);
 #endif
-  fprintf (stderr, "fontset: %d\n", face->fontset);
-  fprintf (stderr, "underline: %d (%s)\n",
-	   face->underline_p,
-	   SDATA (Fsymbol_name (face->lface[LFACE_UNDERLINE_INDEX])));
-  fprintf (stderr, "hash: %" PRIuPTR "\n", face->hash);
+  errprintf ("fontset: %d\n", face->fontset);
+  errprintf ("underline: %d (%s)\n",
+	     face->underline_p,
+	     SDATA (Fsymbol_name (face->lface[LFACE_UNDERLINE_INDEX])));
+  errprintf ("hash: %" PRIuPTR "\n", face->hash);
 }
 
 
@@ -6429,14 +6423,14 @@ DEFUN ("dump-face", Fdump_face, Sdump_face, 0, 1, 0, doc: /* */)
     {
       int i;
 
-      fprintf (stderr, "font selection order: ");
+      errputs ("font selection order: ");
       for (i = 0; i < ARRAYELTS (font_sort_order); ++i)
-	fprintf (stderr, "%d ", font_sort_order[i]);
-      fprintf (stderr, "\n");
+	errprintf ("%d ", font_sort_order[i]);
+      errputc ('\n');
 
-      fprintf (stderr, "alternative fonts: ");
+      errputs ("alternative fonts: ");
       debug_print (Vface_alternative_font_family_alist);
-      fprintf (stderr, "\n");
+      errputc ('\n');
 
       for (i = 0; i < FRAME_FACE_CACHE (SELECTED_FRAME ())->used; ++i)
 	Fdump_face (make_fixnum (i));
@@ -6459,9 +6453,9 @@ DEFUN ("show-face-resources", Fshow_face_resources, Sshow_face_resources,
        0, 0, 0, doc: /* */)
   (void)
 {
-  fprintf (stderr, "number of colors = %d\n", ncolors_allocated);
-  fprintf (stderr, "number of pixmaps = %d\n", npixmaps_allocated);
-  fprintf (stderr, "number of GCs = %d\n", ngcs);
+  errprintf ("number of colors = %d\n", ncolors_allocated);
+  errprintf ("number of pixmaps = %d\n", npixmaps_allocated);
+  errprintf ("number of GCs = %d\n", ngcs);
   return Qnil;
 }
 
diff --git a/src/xfns.c b/src/xfns.c
index b8a1914186..24c01ace58 100644
--- a/src/xfns.c
+++ b/src/xfns.c
@@ -2384,13 +2384,13 @@ print_fontset_result (XFontSet xfs, char *name, char **missing_list,
 		      int missing_count)
 {
   if (xfs)
-    fprintf (stderr, "XIC Fontset created: %s\n", name);
+    errprintf ("XIC Fontset created: %s\n", name);
   else
     {
-      fprintf (stderr, "XIC Fontset failed: %s\n", name);
+      errprintf ("XIC Fontset failed: %s\n", name);
       while (missing_count-- > 0)
 	{
-	  fprintf (stderr, "  missing: %s\n", *missing_list);
+	  errprintf ("  missing: %s\n", *missing_list);
 	  missing_list++;
 	}
     }
diff --git a/src/xmenu.c b/src/xmenu.c
index 22d1cc21aa..2f952f363e 100644
--- a/src/xmenu.c
+++ b/src/xmenu.c
@@ -2321,7 +2321,7 @@ x_menu_show (struct frame *f, int x, int y, int menuflags,
     {
     case XM_SUCCESS:
 #ifdef XDEBUG
-      fprintf (stderr, "pane= %d line = %d\n", panes, selidx);
+      errprintf ("pane= %d line = %d\n", panes, selidx);
 #endif
 
       /* Find the item number SELIDX in pane number PANE.  */
diff --git a/src/xrdb.c b/src/xrdb.c
index 9c625e9821..4dbc7cee30 100644
--- a/src/xrdb.c
+++ b/src/xrdb.c
@@ -589,7 +589,7 @@ member (char *elt, List list)
 static void
 fatal (char *msg, char *prog)
 {
-  fprintf (stderr, msg, prog);
+  errprintf (msg, prog);
   exit (1);
 }
 
diff --git a/src/xselect.c b/src/xselect.c
index 5f0bb44cc9..6268e74d8e 100644
--- a/src/xselect.c
+++ b/src/xselect.c
@@ -21,7 +21,6 @@
 
 #include <config.h>
 #include <limits.h>
-#include <stdio.h>      /* termhooks.h needs this */
 
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>
@@ -33,6 +32,7 @@
 #include "xterm.h"	/* for all of the X includes */
 #include "frame.h"	/* Need this to get the X window of selected_frame */
 #include "blockinput.h"
+#include "sysstdio.h"
 #include "termhooks.h"
 #include "keyboard.h"
 #include "pdumper.h"
@@ -63,13 +63,13 @@
 
 #ifdef TRACE_SELECTION
 #define TRACE0(fmt) \
-  fprintf (stderr, "%"pMd": " fmt "\n", (printmax_t) getpid ())
+  errprintf ("%"pMd": " fmt "\n", (printmax_t) getpid ())
 #define TRACE1(fmt, a0) \
-  fprintf (stderr, "%"pMd": " fmt "\n", (printmax_t) getpid (), a0)
+  errprintf ("%"pMd": " fmt "\n", (printmax_t) getpid (), a0)
 #define TRACE2(fmt, a0, a1) \
-  fprintf (stderr, "%"pMd": " fmt "\n", (printmax_t) getpid (), a0, a1)
+  errprintf ("%"pMd": " fmt "\n", (printmax_t) getpid (), a0, a1)
 #define TRACE3(fmt, a0, a1, a2) \
-  fprintf (stderr, "%"pMd": " fmt "\n", (printmax_t) getpid (), a0, a1, a2)
+  errprintf ("%"pMd": " fmt "\n", (printmax_t) getpid (), a0, a1, a2)
 #else
 #define TRACE0(fmt)		(void) 0
 #define TRACE1(fmt, a0)		(void) 0
@@ -2172,7 +2172,7 @@ x_clipboard_manager_error_1 (Lisp_Object err)
 static Lisp_Object
 x_clipboard_manager_error_2 (Lisp_Object err)
 {
-  fprintf (stderr, "Error saving to X clipboard manager.\n\
+  errprintf ("Error saving to X clipboard manager.\n\
 If the problem persists, set '%s' \
 to nil.\n", "x-select-enable-clipboard-manager");
   return Qnil;
diff --git a/src/xsmfns.c b/src/xsmfns.c
index 1706cddf27..e2e544516c 100644
--- a/src/xsmfns.c
+++ b/src/xsmfns.c
@@ -29,10 +29,10 @@ Copyright (C) 2002-2019 Free Software Foundation, Inc.
 #include <unistd.h>
 #include <sys/param.h>
 #include <errno.h>
-#include <stdio.h>
 
 #include "lisp.h"
 #include "frame.h"
+#include "sysstdio.h"
 #include "termhooks.h"
 #include "xterm.h"
 #include "process.h"
@@ -404,8 +404,8 @@ #define SM_ERRORSTRING_LEN 512
   char *pwd = emacs_get_current_dir_name ();
   if (!pwd)
     {
-      fprintf (stderr, "Disabling session management due to pwd error: %s\n",
-               emacs_strerror (errno));
+      errprintf ("Disabling session management due to pwd error: %s\n",
+		 emacs_strerror (errno));
       return;
     }
   xfree (pwd);
diff --git a/src/xterm.c b/src/xterm.c
index 38bc17de97..7fea1946eb 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -21,12 +21,12 @@ Copyright (C) 1989, 1993-2019 Free Software Foundation, Inc.
 /* Xt features made by Fred Pierresteguy.  */
 
 #include <config.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include <math.h>
 
 #include "lisp.h"
 #include "blockinput.h"
+#include "sysstdio.h"
 
 /* This may include sys/types.h, and that somehow loses
    if this is not done before the other system files.  */
@@ -9876,7 +9876,7 @@ x_fully_uncatch_errors (void)
 static unsigned int x_wire_count;
 x_trace_wire (void)
 {
-  fprintf (stderr, "Lib call: %d\n", ++x_wire_count);
+  errprintf ("Lib call: %d\n", ++x_wire_count);
 }
 #endif
 
@@ -9954,11 +9954,11 @@ x_connection_closed (Display *dpy, const char *error_message, bool ioerror)
 	 the resulting Glib error message loop filled a user's disk.
 	 To avoid this, kill Emacs unconditionally on disconnect.  */
       shut_down_emacs (0, Qnil);
-      fprintf (stderr, "%s\n\
+      errprintf ("%s\n\
 When compiled with GTK, Emacs cannot recover from X disconnects.\n\
 This is a GTK bug: https://gitlab.gnome.org/GNOME/gtk/issues/221\n\
 For details, see etc/PROBLEMS.\n",
-	       error_msg);
+		 error_msg);
       emacs_abort ();
 #endif /* USE_GTK */
 
@@ -9980,7 +9980,7 @@ x_connection_closed (Display *dpy, const char *error_message, bool ioerror)
 
   if (terminal_list == 0)
     {
-      fprintf (stderr, "%s\n", error_msg);
+      errprintf ("%s\n", error_msg);
       Fkill_emacs (make_fixnum (70));
       /* NOTREACHED */
     }
@@ -12465,7 +12465,7 @@ my_log_handler (const gchar *log_domain, GLogLevelFlags log_level,
 		const gchar *msg, gpointer user_data)
 {
   if (!strstr (msg, "g_set_prgname"))
-      fprintf (stderr, "%s-WARNING **: %s\n", log_domain, msg);
+    errprintf ("%s-WARNING **: %s\n", log_domain, msg);
 }
 #endif
 
@@ -13441,8 +13441,7 @@ x_initialize (void)
 #if THREADS_ENABLED
   /* This must be called before any other Xlib routines.  */
   if (XInitThreads () == 0)
-    fprintf (stderr,
-	     "Warning: An error occurred initializing X11 thread support!\n");
+    errputs ("Warning: An error occurred initializing X11 thread support!\n");
 #endif
 
 #ifdef USE_X_TOOLKIT
-- 
2.21.0