Fix fseeko/ftello on cygwin 1.5.24.

* doc/functions/fseeko.texi (fseeko): Document the fix.
* doc/functions/ftello.texi (ftello): Document the fix.
* doc/functions/stdin.texi (stdin): Document the cygwin bug.
* doc/functions/stdout.text (stdout): New file.
* doc/functions/stderr.text (stderr): New file.
* doc/gnulib.texi (Function Substitutes): Use new files.
* tests/test-fseeko.c (main): Check for broken fseeko on cygwin
prior to 1.7.0.
* tests/test-ftello.c (main): Likewise for ftello.
* tests/test-fseeko.sh: New file.
* tests/test-ftello.sh: New file.
* modules/fseeko-tests (Makefile.am): Ensure test-fseeko is run
with seekable stdin.
* modules/ftello-tests (Makefile.am): Likewise for test-ftello.
* m4/fseeko.m4 (gl_FUNC_FSEEKO): Detect the cygwin bug.
(gl_REPLACE_FSEEKO): New macro.
* m4/ftello.m4 (gl_FUNC_FTELLO, gl_REPLACE_FTELLO): Likewise.
* modules/fseeko (Files): Distribute fseeko.c.
* modules/ftello (Files): Distribute ftello.c.
* lib/fseeko.c (rpl_fseeko) [__CYGWIN__]: Convert stdin to 64-bit
mode.
* lib/ftello.c (rpl_ftello): New file.
* m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Allow replacement of
fseeko, ftello.
(gl_STDIN_LARGE_OFFSET): New macro.
* modules/stdio (Makefile.am): Perform the replacement.
* lib/stdio_.h (rpl_fseeko, rpl_ftello): Define when needed.

22 files changed, 230 insertions, 22 deletions

diff --git a/ChangeLog b/ChangeLog
index 8d8868cd9e..e99058d8d9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,34 @@
+2007-05-23  Eric Blake  <ebb9@byu.net>
+
+	Fix fseeko/ftello on cygwin 1.5.24.
+	* doc/functions/fseeko.texi (fseeko): Document the fix.
+	* doc/functions/ftello.texi (ftello): Document the fix.
+	* doc/functions/stdin.texi (stdin): Document the cygwin bug.
+	* doc/functions/stdout.text (stdout): New file.
+	* doc/functions/stderr.text (stderr): New file.
+	* doc/gnulib.texi (Function Substitutes): Use new files.
+	* tests/test-fseeko.c (main): Check for broken fseeko on cygwin
+	prior to 1.7.0.
+	* tests/test-ftello.c (main): Likewise for ftello.
+	* tests/test-fseeko.sh: New file.
+	* tests/test-ftello.sh: New file.
+	* modules/fseeko-tests (Makefile.am): Ensure test-fseeko is run
+	with seekable stdin.
+	* modules/ftello-tests (Makefile.am): Likewise for test-ftello.
+	* m4/fseeko.m4 (gl_FUNC_FSEEKO): Detect the cygwin bug.
+	(gl_REPLACE_FSEEKO): New macro.
+	* m4/ftello.m4 (gl_FUNC_FTELLO, gl_REPLACE_FTELLO): Likewise.
+	* modules/fseeko (Files): Distribute fseeko.c.
+	* modules/ftello (Files): Distribute ftello.c.
+	* lib/fseeko.c (rpl_fseeko) [__CYGWIN__]: Convert stdin to 64-bit
+	mode.
+	* lib/ftello.c (rpl_ftello): New file.
+	* m4/stdio_h.m4 (gl_STDIO_H_DEFAULTS): Allow replacement of
+	fseeko, ftello.
+	(gl_STDIN_LARGE_OFFSET): New macro.
+	* modules/stdio (Makefile.am): Perform the replacement.
+	* lib/stdio_.h (rpl_fseeko, rpl_ftello): Define when needed.
+
 2007-05-23  Bruno Haible  <bruno@clisp.org>
 
 	* lib/stdio_.h (fseeko, ftello): Provide a link warning only if
diff --git a/doc/functions/fseeko.texi b/doc/functions/fseeko.texi
index d724e59da2..7d8c0a6aaf 100644
--- a/doc/functions/fseeko.texi
+++ b/doc/functions/fseeko.texi
@@ -14,6 +14,8 @@ OSF/1 4.0, Solaris 2.5.1, mingw.
 @item
 The declaration of @code{fseeko} in @code{<stdio.h>} is not enabled by default
 on some platforms: glibc 2.3.6.
+@item
+This function fails on seekable stdin, stdout, and stderr: cygwin 1.5.x.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/doc/functions/ftello.texi b/doc/functions/ftello.texi
index af16b3dee8..d6789b7528 100644
--- a/doc/functions/ftello.texi
+++ b/doc/functions/ftello.texi
@@ -14,6 +14,8 @@ OSF/1 4.0, Solaris 2.5.1, mingw.
 @item
 The declaration of @code{ftello} in @code{<stdio.h>} is not enabled by default
 on some platforms: glibc 2.3.6.
+@item
+This function fails on seekable stdin, stdout, and stderr: cygwin 1.5.x.
 @end itemize
 
 Portability problems not fixed by Gnulib:
diff --git a/doc/functions/stderr.texi b/doc/functions/stderr.texi
new file mode 100644
index 0000000000..66f594266e
--- /dev/null
+++ b/doc/functions/stderr.texi
@@ -0,0 +1,20 @@
+@node stderr
+@section @code{stderr}
+@findex stderr
+
+POSIX specification: @url{http://www.opengroup.org/susv3xsh/stderr.html}
+
+Gnulib module: ---
+
+Portability problems fixed by Gnulib:
+@itemize
+@end itemize
+
+Portability problems not fixed by Gnulib:
+@itemize
+@item
+stderr is created in 32-bit mode instead of 64-bit mode: Cygwin 1.5.x.
+One workaround is to use freopen(NULL, ``r+'', stderr) on Cygwin 1.5.21
+or newer.  Another is to use the gnulib ftello module and do
+ftello(stderr).
+@end itemize
diff --git a/doc/functions/stdin.texi b/doc/functions/stdin.texi
index 5a4f852a14..7a597e67fc 100644
--- a/doc/functions/stdin.texi
+++ b/doc/functions/stdin.texi
@@ -12,4 +12,9 @@ Portability problems fixed by Gnulib:
 
 Portability problems not fixed by Gnulib:
 @itemize
+@item
+stdin is created in 32-bit mode instead of 64-bit mode: Cygwin 1.5.x.
+One workaround is to use freopen(NULL, ``r'', stdin) on Cygwin 1.5.21
+or newer.  Another is to use the gnulib ftello module and do
+ftello(stdin).
 @end itemize
diff --git a/doc/functions/stdout.texi b/doc/functions/stdout.texi
new file mode 100644
index 0000000000..b9544c8826
--- /dev/null
+++ b/doc/functions/stdout.texi
@@ -0,0 +1,20 @@
+@node stdout
+@section @code{stdout}
+@findex stdout
+
+POSIX specification: @url{http://www.opengroup.org/susv3xsh/stdout.html}
+
+Gnulib module: ---
+
+Portability problems fixed by Gnulib:
+@itemize
+@end itemize
+
+Portability problems not fixed by Gnulib:
+@itemize
+@item
+stdout is created in 32-bit mode instead of 64-bit mode: Cygwin 1.5.x.
+One workaround is to use freopen(NULL, ``w'', stdout) on Cygwin 1.5.21
+or newer.  Another is to use the gnulib ftello module and do
+ftello(stdout).
+@end itemize
diff --git a/doc/gnulib.texi b/doc/gnulib.texi
index ab537300ec..34e893672e 100644
--- a/doc/gnulib.texi
+++ b/doc/gnulib.texi
@@ -1,5 +1,5 @@
 \input texinfo   @c -*-texinfo-*-
-@comment $Id: gnulib.texi,v 1.40 2007-05-01 22:37:10 haible Exp $
+@comment $Id: gnulib.texi,v 1.41 2007-05-24 03:53:38 ericb Exp $
 @comment %**start of header
 @setfilename gnulib.info
 @settitle GNU Gnulib
@@ -7,7 +7,7 @@
 @syncodeindex pg cp
 @comment %**end of header
 
-@set UPDATED $Date: 2007-05-01 22:37:10 $
+@set UPDATED $Date: 2007-05-24 03:53:38 $
 
 @copying
 This manual is for GNU Gnulib (updated @value{UPDATED}),
@@ -1543,7 +1543,9 @@ by Gnulib.
 * sscanf::
 * stat::
 * statvfs::
+* stderr::
 * stdin::
+* stdout::
 * strcasecmp::
 * strcat::
 * strchr::
@@ -2659,7 +2661,9 @@ by Gnulib.
 @include functions/sscanf.texi
 @include functions/stat.texi
 @include functions/statvfs.texi
+@include functions/stderr.texi
 @include functions/stdin.texi
+@include functions/stdout.texi
 @include functions/strcasecmp.texi
 @include functions/strcat.texi
 @include functions/strchr.texi
@@ -2877,3 +2881,8 @@ generated automatically.
 @printindex cp
 
 @bye
+
+@c Local Variables:
+@c indent-tabs-mode: nil
+@c whitespace-check-buffer-indent: nil
+@c End:
diff --git a/lib/fseeko.c b/lib/fseeko.c
index adb6c64f39..cece4911cc 100644
--- a/lib/fseeko.c
+++ b/lib/fseeko.c
@@ -44,6 +44,19 @@ rpl_fseeko (FILE *fp, off_t offset, int whence)
 # else                                         /* FreeBSD, MacOS X, Cygwin */
 #  define fp_ub fp->_ub
 # endif
+# if defined __SL64 && defined __SCLE /* Cygwin */
+  if ((fp->_flags & __SL64) == 0)
+    {
+      /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
+	 mode; but has an fseeko that requires 64-bit mode.  */
+      FILE *tmp = fopen ("/dev/null", "r");
+      if (!tmp)
+	return -1;
+      fp->_flags |= __SL64;
+      fp->_seek64 = tmp->_seek64;
+      fclose (tmp);
+    }
+# endif
   if (fp->_p == fp->_bf._base
       && fp->_r == 0
       && fp->_w == ((fp->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
@@ -53,10 +66,10 @@ rpl_fseeko (FILE *fp, off_t offset, int whence)
 #elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, mingw */
 # if defined __sun && defined __sparc && defined _LP64 /* Solaris/SPARC 64-bit */
 #  define fp_ ((struct { unsigned char *_ptr; \
-                         unsigned char *_base; \
-                         unsigned char *_end; \
-                         long _cnt; \
-                       } *) fp)
+			 unsigned char *_base; \
+			 unsigned char *_end; \
+			 long _cnt; \
+		       } *) fp)
   if (fp_->_ptr == fp_->_base
       && (fp_->_ptr == NULL || fp_->_cnt == 0))
 # else
diff --git a/lib/ftello.c b/lib/ftello.c
new file mode 100644
index 0000000000..7054dd5b2a
--- /dev/null
+++ b/lib/ftello.c
@@ -0,0 +1,45 @@
+/* An ftello() function that works around platform bugs.
+   Copyright (C) 2007 Free Software Foundation, Inc.
+
+   This program 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 2, or (at your option)
+   any later version.
+
+   This program 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 this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <stdio.h>
+
+#undef ftello
+#if !HAVE_FTELLO
+# define ftello ftell
+#endif
+
+off_t
+rpl_ftello (FILE *fp)
+{
+#if defined __SL64 && defined __SCLE /* Cygwin */
+  if ((fp->_flags & __SL64) == 0)
+    {
+      /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
+	 mode; but has an ftello that requires 64-bit mode.  */
+      FILE *tmp = fopen ("/dev/null", "r");
+      if (!tmp)
+	return -1;
+      fp->_flags |= __SL64;
+      fp->_seek64 = tmp->_seek64;
+      fclose (tmp);
+    }
+#endif
+  return ftello (fp);
+}
diff --git a/lib/stdio_.h b/lib/stdio_.h
index 93ef31a542..f429caaf71 100644
--- a/lib/stdio_.h
+++ b/lib/stdio_.h
@@ -42,7 +42,9 @@
 #include <stdarg.h>
 #include <stddef.h>
 
-#if (@GNULIB_FFLUSH@ && @REPLACE_FFLUSH@) || (@GNULIB_FSEEKO@ && !@HAVE_FSEEKO@) || (@GNULIB_FTELLO@ && !@HAVE_FTELLO@)
+#if (@GNULIB_FFLUSH@ && @REPLACE_FFLUSH@)                               \
+  || (@GNULIB_FSEEKO@ && (!@HAVE_FSEEKO@ || @REPLACE_FSEEKO@))          \
+  || (@GNULIB_FTELLO@ && (!@HAVE_FTELLO@ || @REPLACE_FTELLO@))
 /* Get off_t.  */
 # include <sys/types.h>
 #endif
@@ -216,7 +218,7 @@ extern int vsprintf (char *str, const char *format, va_list args)
 # endif
 #endif
 
-#if @GNULIB_FFLUSH@ && @REPLACE_FFLUSH@
+#if (@GNULIB_FFLUSH@ && @REPLACE_FFLUSH@) || (@GNULIB_FSEEKO@ && @REPLACE_FSEEKO@)
 /* Provide fseek, fseeko functions that are aware of a preceding fflush().  */
 # define fseeko rpl_fseeko
 extern int fseeko (FILE *fp, off_t offset, int whence);
@@ -250,6 +252,9 @@ typedef int verify_fseeko_types[2 * (sizeof (off_t) == sizeof (long)) - 1];
 /* Assume 'off_t' is the same type as 'long'.  */
 typedef int verify_ftello_types[2 * (sizeof (off_t) == sizeof (long)) - 1];
 #  define ftello ftell
+# elif @REPLACE_FTELLO@
+#  define ftello rpl_ftello
+extern off_t ftello (FILE *fp);
 # endif
 #elif defined GNULIB_POSIXCHECK
 # undef ftello
diff --git a/m4/fseeko.m4 b/m4/fseeko.m4
index 86d42f40cc..3d79276f78 100644
--- a/m4/fseeko.m4
+++ b/m4/fseeko.m4
@@ -1,4 +1,4 @@
-# fseeko.m4 serial 1
+# fseeko.m4 serial 2
 dnl Copyright (C) 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -8,12 +8,22 @@ AC_DEFUN([gl_FUNC_FSEEKO],
 [
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
   AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
   AC_CACHE_CHECK([for fseeko], [gl_cv_func_fseeko],
     [
       AC_TRY_LINK([#include <stdio.h>], [fseeko (stdin, 0, 0);],
-        [gl_cv_func_fseeko=yes], [gl_cv_func_fseeko=no])
+	[gl_cv_func_fseeko=yes], [gl_cv_func_fseeko=no])
     ])
   if test $gl_cv_func_fseeko = no; then
     HAVE_FSEEKO=0
+  elif test $gl_cv_var_stdin_large_offset = no; then
+    gl_REPLACE_FSEEKO
   fi
 ])
+
+AC_DEFUN([gl_REPLACE_FSEEKO],
+[
+  AC_LIBOBJ([fseeko])
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  REPLACE_FSEEKO=1
+])
diff --git a/m4/ftello.m4 b/m4/ftello.m4
index c2b826df8a..474bf53133 100644
--- a/m4/ftello.m4
+++ b/m4/ftello.m4
@@ -1,4 +1,4 @@
-# ftello.m4 serial 1
+# ftello.m4 serial 2
 dnl Copyright (C) 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -8,12 +8,22 @@ AC_DEFUN([gl_FUNC_FTELLO],
 [
   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
   AC_REQUIRE([AC_PROG_CC])
+  AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
   AC_CACHE_CHECK([for ftello], [gl_cv_func_ftello],
     [
       AC_TRY_LINK([#include <stdio.h>], [ftello (stdin);],
-        [gl_cv_func_ftello=yes], [gl_cv_func_ftello=no])
+	[gl_cv_func_ftello=yes], [gl_cv_func_ftello=no])
     ])
   if test $gl_cv_func_ftello = no; then
     HAVE_FTELLO=0
+  elif test $gl_cv_var_stdin_large_offset = no; then
+    gl_REPLACE_FTELLO
   fi
 ])
+
+AC_DEFUN([gl_REPLACE_FTELLO],
+[
+  AC_LIBOBJ([ftello])
+  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
+  REPLACE_FTELLO=1
+])
diff --git a/m4/stdio_h.m4 b/m4/stdio_h.m4
index c696ee2ee7..2cddcc3313 100644
--- a/m4/stdio_h.m4
+++ b/m4/stdio_h.m4
@@ -1,4 +1,4 @@
-# stdio_h.m4 serial 4
+# stdio_h.m4 serial 5
 dnl Copyright (C) 2007 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -47,6 +47,29 @@ AC_DEFUN([gl_STDIO_H_DEFAULTS],
   HAVE_VASPRINTF=1;        AC_SUBST([HAVE_VASPRINTF])
   REPLACE_VASPRINTF=0;     AC_SUBST([REPLACE_VASPRINTF])
   HAVE_FSEEKO=1;           AC_SUBST([HAVE_FSEEKO])
+  REPLACE_FSEEKO=0;        AC_SUBST([REPLACE_FSEEKO])
   HAVE_FTELLO=1;           AC_SUBST([HAVE_FTELLO])
+  REPLACE_FTELLO=0;        AC_SUBST([REPLACE_FTELLO])
   REPLACE_FFLUSH=0;        AC_SUBST([REPLACE_FFLUSH])
 ])
+
+dnl Code shared by fseeko and ftello.  Determine if large files are supported,
+dnl but stdin does not start as a large file by default.
+AC_DEFUN([gl_STDIN_LARGE_OFFSET],
+  [
+    AC_CACHE_CHECK([whether stdin defaults to large file offsets],
+      [gl_cv_var_stdin_large_offset],
+      [AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <stdio.h>],
+[#if defined __SL64 && defined __SCLE /* cygwin */
+  /* Cygwin 1.5.24 and earlier fail to put stdin in 64-bit mode, making
+     fseeko/ftello needlessly fail.  This bug was fixed at the same time
+     that cygwin started exporting asnprintf (cygwin 1.7.0), so we use
+     that as a link-time test for cross-compiles rather than building
+     a runtime test.  */
+  size_t s;
+  if (asnprintf (NULL, &s, ""))
+    return 0;
+#endif])],
+	[gl_cv_var_stdin_large_offset=yes],
+	[gl_cv_var_stdin_large_offset=no])])
+])
diff --git a/modules/fseeko b/modules/fseeko
index e8c10f2d59..af6eccbd1e 100644
--- a/modules/fseeko
+++ b/modules/fseeko
@@ -2,6 +2,7 @@ Description:
 fseeko() function: Reposition a FILE stream.
 
 Files:
+lib/fseeko.c
 m4/fseeko.m4
 
 Depends-on:
diff --git a/modules/fseeko-tests b/modules/fseeko-tests
index 055e2af794..718832af8d 100644
--- a/modules/fseeko-tests
+++ b/modules/fseeko-tests
@@ -1,10 +1,13 @@
 Files:
 tests/test-fseeko.c
+tests/test-fseeko.sh
 
 Depends-on:
 
 configure.ac:
 
 Makefile.am:
-TESTS += test-fseeko
+TESTS += test-fseeko.sh
+TESTS_ENVIRONMENT += EXEEXT='@EXEEXT@' srcdir='$(srcdir)'
 check_PROGRAMS += test-fseeko
+EXTRA_DIST += test-fseeko.sh
diff --git a/modules/ftello b/modules/ftello
index daac684051..2d6b724489 100644
--- a/modules/ftello
+++ b/modules/ftello
@@ -2,6 +2,7 @@ Description:
 ftello() function: Retrieve the position of a FILE stream.
 
 Files:
+lib/ftello.c
 m4/ftello.m4
 
 Depends-on:
diff --git a/modules/ftello-tests b/modules/ftello-tests
index fef9159000..1d4279d1f4 100644
--- a/modules/ftello-tests
+++ b/modules/ftello-tests
@@ -1,10 +1,13 @@
 Files:
 tests/test-ftello.c
+tests/test-ftello.sh
 
 Depends-on:
 
 configure.ac:
 
 Makefile.am:
-TESTS += test-ftello
+TESTS += test-ftello.sh
+TESTS_ENVIRONMENT += EXEEXT='@EXEEXT@' srcdir='$(srcdir)'
 check_PROGRAMS += test-ftello
+EXTRA_DIST += test-ftello.sh
diff --git a/modules/stdio b/modules/stdio
index eba4c8b04f..dd49435c4e 100644
--- a/modules/stdio
+++ b/modules/stdio
@@ -47,7 +47,9 @@ stdio.h: stdio_.h
 	      -e 's|@''HAVE_VASPRINTF''@|$(HAVE_VASPRINTF)|g' \
 	      -e 's|@''REPLACE_VASPRINTF''@|$(REPLACE_VASPRINTF)|g' \
 	      -e 's|@''HAVE_FSEEKO''@|$(HAVE_FSEEKO)|g' \
+	      -e 's|@''REPLACE_FSEEKO''@|$(REPLACE_FSEEKO)|g' \
 	      -e 's|@''HAVE_FTELLO''@|$(HAVE_FTELLO)|g' \
+	      -e 's|@''REPLACE_FTELLO''@|$(REPLACE_FTELLO)|g' \
 	      -e 's|@''REPLACE_FFLUSH''@|$(REPLACE_FFLUSH)|g' \
 	      -e '/definition of GL_LINK_WARNING/r $(LINK_WARNING_H)' \
 	      < $(srcdir)/stdio_.h; \
diff --git a/tests/test-fseeko.c b/tests/test-fseeko.c
index 1b4c9e8d1e..198cbfce3d 100644
--- a/tests/test-fseeko.c
+++ b/tests/test-fseeko.c
@@ -27,8 +27,6 @@
 int
 main ()
 {
-  off_t pos = fseeko (stdin, (off_t)0, SEEK_CUR);
-  (void)pos;
-
-  return 0;
+  /* This test assumes stdin is seekable.  */
+  return fseeko (stdin, (off_t)0, SEEK_CUR) != 0;
 }
diff --git a/tests/test-fseeko.sh b/tests/test-fseeko.sh
new file mode 100755
index 0000000000..d6310c7b9f
--- /dev/null
+++ b/tests/test-fseeko.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+./test-fseeko${EXEEXT} < "$srcdir/test-fseeko.sh"
diff --git a/tests/test-ftello.c b/tests/test-ftello.c
index 3feefe147f..f87783fc26 100644
--- a/tests/test-ftello.c
+++ b/tests/test-ftello.c
@@ -27,8 +27,7 @@
 int
 main ()
 {
+  /* This test assumes stdin is seekable.  */
   off_t pos = ftello (stdin);
-  (void)pos;
-
-  return 0;
+  return pos < 0;
 }
diff --git a/tests/test-ftello.sh b/tests/test-ftello.sh
new file mode 100755
index 0000000000..8774c6e09a
--- /dev/null
+++ b/tests/test-ftello.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+./test-ftello${EXEEXT} < "$srcdir/test-ftello.sh"